diff --git a/dev/js/src/menu.js b/dev/js/src/menu.js
index 4d80419..ecce23b 100644
--- a/dev/js/src/menu.js
+++ b/dev/js/src/menu.js
@@ -25,8 +25,10 @@
              defaultLengthFieldClass,
              sliderClass) {
 
+  "use strict";
+
   // Default maximum number of menu items
-  var menuLimit = 8;
+  const menuLimit = 8;
 
   /**
    * List of items for drop down menu (complete).
@@ -53,166 +55,155 @@
 
     // Initialize list
     _init : function (list, params) {
-
+      
       if (params === undefined)
         params = {};
 
-      this._itemClass = params["itemClass"] || defaultItemClass;
+      const t = this;
+
+      t._itemClass = params["itemClass"] || defaultItemClass;
 
       // Add prefix object
       if (params["prefixClass"] !== undefined) {
-        this._prefix = params["prefixClass"].create();
+        t._prefix = params["prefixClass"].create();
       }
       else {
-        this._prefix = defaultPrefixClass.create();
+        t._prefix = defaultPrefixClass.create();
       };
-      this._prefix._menu = this;
+      t._prefix._menu = t;
 
       // Add lengthField object
       if (params["lengthFieldClass"] !== undefined) {
-        this._lengthField = params["lengthFieldClass"].create();
+        t._lengthField = params["lengthFieldClass"].create();
       }
       else {
-        this._lengthField = defaultLengthFieldClass.create();
+        t._lengthField = defaultLengthFieldClass.create();
       };
-      this._lengthField._menu = this;
+      t._lengthField._menu = t;
 
       // Initialize slider
-      this._slider = sliderClass.create(this);
+      t._slider = sliderClass.create(t);
 
       // Create the element
       var el = document.createElement("ul");
-      with (el) {
-        style.outline = 0;
-        setAttribute('tabindex', 0);
-        classList.add('menu', 'roll');
-        appendChild(this._prefix.element());
-        appendChild(this._lengthField.element());
-        appendChild(this._slider.element());
-      };
+      el.style.outline = 0;
+      el.setAttribute('tabindex', 0);
+      el.classList.add('menu', 'roll');
+      el.appendChild(t._prefix.element());
+      el.appendChild(t._lengthField.element());
+      el.appendChild(t._slider.element());
 
       // This has to be cleaned up later on
-      el["menu"] = this;
+      el["menu"] = t;
 
       // Arrow keys
       el.addEventListener(
         'keydown',
-        this._keydown.bind(this),
+        t._keydown.bind(t),
         false
       );
 
       // Strings
       el.addEventListener(
         'keypress',
-        this._keypress.bind(this),
+        t._keypress.bind(t),
         false
       );
 
       // Mousewheel
       el.addEventListener(
         'wheel',
-        this._mousewheel.bind(this),
+        t._mousewheel.bind(t),
         false
       );
 
-      // Touch
-      el.addEventListener(
-        'touchstart',
-        this._touch.bind(this),
-        false
-      );
-      el.addEventListener(
-        'touchend',
-        this._touch.bind(this),
-        false
-      );
-      el.addEventListener(
-        'touchmove',
-        this._touch.bind(this),
-        false
+      // Touch events
+      ['touchstart', 'touchend', 'touchmove'].forEach(
+        e => el.addEventListener(e, t._touch.bind(t), false)
       );
 
       
-      this._element = el;
+      t._element = el;
 
-      this._limit = menuLimit;
+      t._limit = menuLimit;
       
-      this._items = new Array();
+      t._items = new Array();
 
       // TODO:
       // Make this separate from _init
-      this.readItems(list);
+      t.readItems(list);
 
-      this.dontHide = false;
+      t.dontHide = false;
         
-      return this;
+      return t;
     },
 
     // Read items to add to list
     readItems : function (list) {
+      const t = this;
 
-      this._list = undefined;
+      t._list = undefined;
 
       // Remove circular reference to "this" in items
-      for (var i = 0; i < this._items.length; i++) {
-        delete this._items[i]["_menu"];
-        delete this._items[i];
+      for (let i = 0; i < t._items.length; i++) {
+        delete t._items[i]["_menu"];
+        delete t._items[i];
       };
 
-      this._items = new Array();
-      this.removeItems();
+      t._items = new Array();
+      t.removeItems();
 
 
       // Initialize items
-      this._lengthField.reset();
+      t._lengthField.reset();
 
-      var i = 0;
       // Initialize item list based on parameters
       list.forEach(function(i){
-        var obj = this._itemClass.create(i);
+        const obj = this._itemClass.create(i);
 
         // This may become circular
         obj["_menu"] = this;
         this._lengthField.add(i);
         this._items.push(obj);
-      }, this);
+      }, t);
 
-      this._slider.length(this.liveLength())
-        .limit(this._limit)
+      t._slider.length(t.liveLength())
+        .limit(t._limit)
         .reInit();
       
-      this._firstActive = false;
+      t._firstActive = false;
       // Show the first item active always?
-      this.offset = 0;
-      this.position = 0;
+      t.offset = 0;
+      t.position = 0;
     },
     
     // Initialize the item list
     _initList : function () {
+      const t = this;
 
       // Create a new list
-      if (this._list === undefined) {
-        this._list = [];
+      if (t._list === undefined) {
+        t._list = [];
       }
-      else if (this._list.length !== 0) {
-        this._boundary(false);
-        this._list.length = 0;
+      else if (t._list.length !== 0) {
+        t._boundary(false);
+        t._list.length = 0;
       };
 
       // Offset is initially zero
-      this.offset = 0;
+      t.offset = 0;
 
       // There is no prefix set
-      if (this.prefix().length <= 0) {
+      if (t.prefix().length <= 0) {
 
         // add all items to the list and lowlight
         let i = 0;
-        for (; i < this._items.length; i++) {
-          this._list.push(i);
-          this._items[i].lowlight();
+        for (; i < t._items.length; i++) {
+          t._list.push(i);
+          t._items[i].lowlight();
         };
 
-        this._slider.length(i).reInit();
+        t._slider.length(i).reInit();
 
         return true;
       };
@@ -220,15 +211,15 @@
       /*
        * There is a prefix set, so filter the list!
        */
-      var pos;
-      var prefixList = this.prefix().toLowerCase().split(" ");
+      let pos;
+      const prefixList = t.prefix().toLowerCase().split(" ");
 
-      var items = [];
-      var maxPoints = 1; // minimum 1
+      const items = [];
+      let maxPoints = 1; // minimum 1
 
       // Iterate over all items and choose preferred matching items
       // i.e. the matching happens at the word start
-      this._items.forEach(function(it, pos){
+      t._items.forEach(function(it, pos){
 
         let points = 0;
 
@@ -252,25 +243,12 @@
         else if (points == maxPoints) {
           this._list.push(pos);
         }
-      },this);
+      }, t);
 
-      // The list is empty - so lower your expectations
-      // Iterate over all items and choose matching items
-      // i.e. the matching happens anywhere in the word
-      /*
-      prefix = prefix.substring(1);
-      if (this._list.length == 0) {
-        for (pos = 0; pos < this._items.length; pos++) {
-          if ((this.item(pos).lcField().indexOf(prefix)) >= 0)
-            this._list.push(pos);
-        };
-      };
-      */
-
-      this._slider.length(this._list.length).reInit();
+      t._slider.length(t._list.length).reInit();
 
       // Filter was successful - yeah!
-      return this._list.length > 0 ? true : false;
+      return t._list.length > 0 ? true : false;
     },
 
 
@@ -280,20 +258,21 @@
      * mark and sweep GC)!
      */
     destroy : function () {
+      const t = this;
 
       // Remove circular reference to "this" in menu
-      if (this._element != undefined)
-        delete this._element["menu"]; 
+      if (t._element != undefined)
+        delete t._element["menu"]; 
 
       // Remove circular reference to "this" in items
-      this._items.forEach(function(i) {
+      t._items.forEach(function(i) {
         delete i["_menu"];
       });
 
       // Remove circular reference to "this" in prefix
-      delete this._prefix['_menu'];
-      delete this._lengthField['_menu'];
-      delete this._slider['_menu'];
+      delete t._prefix['_menu'];
+      delete t._lengthField['_menu'];
+      delete t._slider['_menu'];
     },
 
 
@@ -307,8 +286,7 @@
 
     // mouse wheel treatment
     _mousewheel : function (e) {
-      var delta = 0;
-      delta = e.deltaY / 120;
+      const delta = e.deltaY / 120;
       if (delta > 0)
         this.next();
       else if (delta < 0)
@@ -316,33 +294,32 @@
       e.halt();
     },
 
+
     // touchmove treatment
     _touch : function (e) {
-      var s = this.slider();
+      const s = this.slider();
+
       if (e.type === "touchstart") {
-        // s.active(true);
-        var t = e.touches[0];
-        this._lastTouch = t.clientY;
+        this._lastTouch = e.touches[0].clientY;
       }
       else if (e.type === "touchend") {
-        // s.active(false);
         this._lastTouch = undefined;
       }
       else if (e.type === "touchmove") {
-        var t = e.touches[0];
+        const to = e.touches[0];
 
         // TODO:
         // Instead of using 26px, choose the item height
         // or use the menu height // shownItems
         
         // s.movetoRel(t.clientY - this._initTouch);
-        if ((this._lastTouch + 26) < t.clientY) {
+        if ((this._lastTouch + 26) < to.clientY) {
           this.viewDown();
-          this._lastTouch = t.clientY;
+          this._lastTouch = to.clientY;
         }
-        else if ((this._lastTouch - 26) > t.clientY) {
+        else if ((this._lastTouch - 26) > to.clientY) {
           this.viewUp();
-          this._lastTouch = t.clientY;
+          this._lastTouch = to.clientY;
         }
         e.halt();
       };
@@ -350,35 +327,40 @@
 
     // Arrow key and prefix treatment
     _keydown : function (e) {
-      var code = _codeFromEvent(e);
+      const t = this;
 
-      switch (code) {
+      switch (_codeFromEvent(e)) {
+
       case 27: // 'Esc'
         e.halt();
-        this.hide();
+        t.hide();
         break;
 
       case 38: // 'Up'
         e.halt();
-        this.prev();
+        t.prev();
         break;
+
       case 33: // 'Page up'
         e.halt();
-        this.pageUp();
+        t.pageUp();
         break;
+
       case 40: // 'Down'
         e.halt();
-        this.next();
+        t.next();
         break;
+
       case 34: // 'Page down'
         e.halt();
-        this.pageDown();
+        t.pageDown();
         break;
+
       case 39: // 'Right'
-        if (this._prefix.active())
+        if (t._prefix.active())
           break;
 
-        var item = this.liveItem(this.position);
+        const item = t.liveItem(t.position);
         
         if (item["further"] !== undefined) {
           item["further"].bind(item).apply();
@@ -386,42 +368,48 @@
         
         e.halt();
         break;
-      case 13: // 'Enter'
 
+      case 13: // 'Enter'
         // Click on prefix
-        if (this._prefix.active())
-          this._prefix.onclick(e);
+        if (t._prefix.active())
+          t._prefix.onclick(e);
 
         // Click on item
         else
-          this.liveItem(this.position).onclick(e);
+          t.liveItem(t.position).onclick(e);
         e.halt();
         break;
+
       case 8: // 'Backspace'
-        this._prefix.chop();
-        this.show();
+        t._prefix.chop();
+        t.show();
         e.halt();
         break;
       };
     },
 
+
     // Add characters to prefix
     _keypress : function (e) {
       if (e.charCode !== 0) {
         e.halt();
-        var c = String.fromCharCode(_codeFromEvent(e));
         
         // Add prefix
-        this._prefix.add(c);
+        this._prefix.add(
+          String.fromCharCode(_codeFromEvent(e))
+        );
+
         this.show();
       };
     },
 
+
     /**
      * Show a screen with a given offset
      * in the viewport.
      */
     screen : function (nr) {
+      const t = this;
 
       // Normalize negative values
       if (nr < 0) {
@@ -429,20 +417,20 @@
       }
 
       // The shown list already shows everything
-      else if (this.liveLength() < this.limit()) {
+      else if (t.liveLength() < t.limit()) {
         return false;
       }
 
       // Move relatively to the next screen
-      else if (nr > (this.liveLength() - this.limit())) {
-        nr = (this.liveLength() - this.limit());
+      else if (nr > (t.liveLength() - t.limit())) {
+        nr = (t.liveLength() - t.limit());
       };
 
       // no change
-      if (this.offset === nr)
+      if (t.offset === nr)
         return false;
 
-      this._showItems(nr);
+      t._showItems(nr);
 
       return true;
     },
@@ -455,6 +443,7 @@
       return this._element;
     },
 
+
     /**
      * Get the creator class for items
      */
@@ -462,6 +451,7 @@
       return this._itemClass;
     },
 
+
     /**
      * Get and set the numerical value
      * for the maximum number of items visible.
@@ -499,24 +489,25 @@
      * @param {string} Prefix for filtering the list
      */
     show : function (active) {
+      const t = this;
 
       // show menu based on initial offset
-      this._unmark();     // Unmark everything that was marked before
-      this.removeItems();
+      t._unmark();     // Unmark everything that was marked before
+      t.removeItems();
 
       // Initialize the list
-      if (!this._initList()) {
+      if (!t._initList()) {
 
         // The prefix is not active
-        this._prefix.active(true);
+        t._prefix.active(true);
 
         // finally show the element
-        this._element.classList.add('visible');
+        t._element.classList.add('visible');
         
         return true;
       };
 
-      var offset = 0;
+      let offset = 0;
 
       // Set a chosen value to active and move the viewport
       if (arguments.length === 1) {
@@ -525,47 +516,48 @@
         if (active < 0) {
           active = 0;
         }
-        else if (active >= this.liveLength()) {
-          active = this.liveLength() - 1;
+        else if (active >= t.liveLength()) {
+          active = t.liveLength() - 1;
         };
 
         // Item is outside the first viewport
-        if (active >= this._limit) {
+        if (active >= t._limit) {
           offset = active;
-          if (offset > (this.liveLength() - this._limit)) {
-            offset = this.liveLength() - this._limit;
+          const newOffset = t.liveLength() - t._limit;
+          if (offset > newOffset) {
+            offset = newOffset;
           };
         };
         
-        this.position = active;
+        t.position = active;
       }
 
       // Choose the first item
-      else if (this._firstActive) {
-        this.position = 0;
+      else if (t._firstActive) {
+        t.position = 0;
       }
 
       // Choose no item
       else {
-        this.position = -1;
+        t.position = -1;
       };
 
-      this.offset = offset;
-      this._showItems(offset); // Show new item list
+      t.offset = offset;
+      t._showItems(offset); // Show new item list
 
       // Make chosen value active
-      if (this.position !== -1) {
-        this.liveItem(this.position).active(true);
+      if (t.position !== -1) {
+        t.liveItem(t.position).active(true);
       };
 
       // The prefix is not active
-      this._prefix.active(false);
+      t._prefix.active(false);
 
       // finally show the element
-      this._element.classList.add('visible');
+      t._element.classList.add('visible');
 
       // Add classes for rolling menus
-      this._boundary(true);
+      t._boundary(true);
 
       return true;
     },
@@ -575,21 +567,23 @@
      * Hide the menu and call the onHide callback.
      */
     hide : function () {
-      if(!this.dontHide){
-          this.removeItems();
-          this._prefix.clear();
-          this.onHide();
-          this._element.classList.remove('visible');
-      } 
-       /* this._element.blur(); */
+      if (!this.dontHide) {
+        this.removeItems();
+        this._prefix.clear();
+        this.onHide();
+        this._element.classList.remove('visible');
+      }
+      // this._element.blur();
     },
 
+
     /**
      * Function released when the menu hides.
      * This method is expected to be overridden.
      */
     onHide : function () {},
 
+
     /**
      * Get the prefix for filtering,
      * e.g. &quot;ve&quot; for &quot;verb&quot;
@@ -602,6 +596,7 @@
       return this._prefix.value();
     },
 
+    
     /**
      * Get the lengthField object.
      */
@@ -609,6 +604,7 @@
       return this._lengthField;
     },
 
+
     /**
      * Get the associated slider object.
      */
@@ -621,18 +617,18 @@
      * Delete all visible items from the menu element
      */
     removeItems : function () {
-      var child;
-
       // Remove all children
-      var children = this._element.childNodes;
+      const children = this._element.childNodes;
+
       // Leave the prefix and lengthField
-      for (var i = children.length - 1; i >= 3; i--) {
+      for (let i = children.length - 1; i >= 3; i--) {
         this._element.removeChild(
           children[i]
         );
       };
     },
 
+
     /**
      * Get a specific item from the complete list
      *
@@ -667,6 +663,7 @@
     shownItem : function (index) {
       if (index >= this.limit())
         return;
+
       return this.liveItem(this.offset + index);
     },
 
@@ -693,124 +690,128 @@
      * Make the next item in the filtered menu active
      */
     next : function () {
+      const t = this;
 
       // No list
-      if (this.liveLength() === 0)
+      if (t.liveLength() === 0)
         return;
 
       // Deactivate old item
-      if (this.position !== -1 && !this._prefix.active()) {
-        this.liveItem(this.position).active(false);
+      if (t.position !== -1 && !t._prefix.active()) {
+        t.liveItem(t.position).active(false);
       };
 
       // Get new active item
-      this.position++;
-      var newItem = this.liveItem(this.position);
+      t.position++;
+      let newItem = t.liveItem(t.position);
 
       // The next element is undefined - roll to top or to prefix
       if (newItem === undefined) {
 
         // Activate prefix
-        var prefix = this._prefix;
+        const prefix = this._prefix;
 
         // Prefix is set and not active - choose!
         if (prefix.isSet() && !prefix.active()) {
-          this.position--;
+          t.position--;
           prefix.active(true);
           return;
         }
 
         // Choose first item
         else {
-          newItem = this.liveItem(0);
+          newItem = t.liveItem(0);
           // choose first item
-          this.position = 0;
-          this._showItems(0);
+          t.position = 0;
+          t._showItems(0);
         };
       }
 
       // The next element is after the viewport - roll down
-      else if (this.position >= (this.limit() + this.offset)) {
-        this.screen(this.position - this.limit() + 1);
+      else if (t.position >= (t.limit() + t.offset)) {
+        t.screen(t.position - t.limit() + 1);
       }
 
       // The next element is before the viewport - roll up
-      else if (this.position <= this.offset) {
-        this.screen(this.position);
+      else if (t.position <= t.offset) {
+        t.screen(t.position);
       };
 
-      this._prefix.active(false);
+      t._prefix.active(false);
       newItem.active(true);
     },
 
+
     /*
      * Make the previous item in the menu active
      */
     prev : function () {
+      const t = this;
 
       // No list
-      if (this.liveLength() === 0)
+      if (t.liveLength() === 0)
         return;
 
       // Deactivate old item
-      if (!this._prefix.active()) {
+      if (!t._prefix.active()) {
 
         // No active element set
-        if (this.position === -1) {
-          this.position = this.liveLength();
+        if (t.position === -1) {
+          t.position = t.liveLength();
         }
 
         // No active element set
         else {
-          this.liveItem(this.position--).active(false);
+          t.liveItem(t.position--).active(false);
         };
       };
 
       // Get new active item
-      var newItem = this.liveItem(this.position);
+      let newItem = t.liveItem(t.position);
 
       // The previous element is undefined - roll to bottom
       if (newItem === undefined) {
 
         // Activate prefix
-        var prefix = this._prefix;
-        var offset =  this.liveLength() - this.limit();
+        const prefix = t._prefix;
+        let offset =  t.liveLength() - t.limit();
         
         // Normalize offset
         offset = offset < 0 ? 0 : offset;
 
         // Choose the last item
-        this.position = this.liveLength() - 1;
+        t.position = t.liveLength() - 1;
         
         // Prefix is set and not active - choose!
         if (prefix.isSet() && !prefix.active()) {
-          this.position++;
+          t.position++;
           prefix.active(true);
-          this.offset = offset;
+          t.offset = offset;
           return;
         }
 
         // Choose last item
         else {
-          newItem = this.liveItem(this.position);
-          this._showItems(offset);
+          newItem = t.liveItem(t.position);
+          t._showItems(offset);
         };
       }
 
       // The previous element is before the view - roll up
-      else if (this.position < this.offset) {
-        this.screen(this.position);
+      else if (t.position < t.offset) {
+        t.screen(t.position);
       }
 
       // The previous element is after the view - roll down
-      else if (this.position >= (this.limit() + this.offset)) {
-        this.screen(this.position - this.limit() + 2);
+      else if (t.position >= (t.limit() + t.offset)) {
+        t.screen(t.position - t.limit() + 2);
       };
 
-      this._prefix.active(false);
+      t._prefix.active(false);
       newItem.active(true);
     },
 
+
     /**
      * Move the page up by limit!
      */
@@ -842,19 +843,22 @@
       this.screen(this.offset + 1);
     },
 
+
     // Unmark all items
     _unmark : function () {
       this._list.forEach(function(it){
-        var item = this._items[it];
+        const item = this._items[it];
         item.lowlight();
         item.active(false);
       }, this);
     },
 
+
     // Set boundary for viewport
     _boundary : function (bool) {
       if (this._list.length === 0)
         return;
+
       this.item(this._list[0]).noMore(bool);
       this.item(this._list[this._list.length - 1]).noMore(bool);
     },
@@ -862,68 +866,68 @@
 
     // Append Items that should be shown
     _showItems : function (off) {
+      const t = this;
 
       // optimization: scroll down one step
-      if (this.offset === (off - 1)) {
-        this.offset = off;
+      if (t.offset === (off - 1)) {
+        t.offset = off;
 
         // Remove the HTML node from the first item
         // leave lengthField/prefix/slider
-        this._element.removeChild(this._element.children[3]);
-        var pos = this.offset + this.limit() - 1;
-        this._append(this._list[pos]);
+        t._element.removeChild(t._element.children[3]);
+
+        t._append(
+          t._list[t.offset + t.limit() - 1]
+        );
       }
 
       // optimization: scroll up one step
-      else if (this.offset === (off + 1)) {
-        this.offset = off;
+      else if (t.offset === (off + 1)) {
+        t.offset = off;
 
         // Remove the HTML node from the last item
-        this._element.removeChild(this._element.lastChild);
+        t._element.removeChild(t._element.lastChild);
 
-        this._prepend(this._list[this.offset]);
+        t._prepend(t._list[t.offset]);
       }
+
       else {
-        this.offset = off;
+        t.offset = off;
 
         // Remove all items
-        this.removeItems();
+        t.removeItems();
 
         // Use list
-        var shown = 0;
-        var i;
+        let shown = 0;
 
-        for (let i = 0; i < this._list.length; i++) {
+        for (let i = 0; i < t._list.length; i++) {
 
           // Don't show - it's before offset
           shown++;
           if (shown <= off)
             continue;
 
-          var itemNr = this._list[i];
-          var item = this.item(itemNr);
-          this._append(itemNr);
+          t._append(t._list[i]);
           
-          if (shown >= (this.limit() + off))
+          if (shown >= (t.limit() + off))
             break;
         };
       };
 
       // set the slider to the new offset
-      this._slider.offset(this.offset);
+      t._slider.offset(t.offset);
     },
 
 
     // Append item to the shown list based on index
     _append : function (i) {
-      var item = this.item(i);
+      const item = this.item(i);
 
       // Highlight based on prefix
       if (this.prefix().length > 0) {
         item.highlight(this.prefix().toLowerCase());
       };
 
-
       // Append element
       this.element().appendChild(item.element());
     },
@@ -931,14 +935,14 @@
 
     // Prepend item to the shown list based on index
     _prepend : function (i) {
-      var item = this.item(i);
+      const item = this.item(i);
 
       // Highlight based on prefix
       if (this.prefix().length > 0) {
         item.highlight(this.prefix().toLowerCase());
       };
 
-      var e = this.element();
+      const e = this.element();
 
       // Append element after lengthField/prefix/slider
       e.insertBefore(
diff --git a/dev/js/src/menu/item.js b/dev/js/src/menu/item.js
index f0c531f..7ce7455 100644
--- a/dev/js/src/menu/item.js
+++ b/dev/js/src/menu/item.js
@@ -23,6 +23,7 @@
     return Object.create(this)._init(params);
   },
 
+
   /**
    * Upgrade this object to another object,
    * while private data stays intact.
@@ -30,7 +31,7 @@
    * @param {Object] An object with properties.
    */
   upgradeTo : function (props) {
-    for (var prop in props) {
+    for (let prop in props) {
       this[prop] = props[prop];
     };
     return this;
@@ -46,6 +47,7 @@
     return this._content;
   },
 
+
   /**
    * Get or set the information for action of this item. 
    */
@@ -71,7 +73,7 @@
    * @param {boolean|null} State of activity
    */
   active : function (bool) {
-    var cl = this.element().classList;
+    const cl = this.element().classList;
     if (bool === undefined)
       return cl.contains("active");
     else if (bool)
@@ -80,6 +82,7 @@
       cl.remove("active");
   },
 
+
   /**
    * Check or set if the item is
    * at the boundary of the menu
@@ -88,7 +91,7 @@
    * @param {boolean|null} State of activity
    */
   noMore : function (bool) {
-    var cl = this.element().classList;
+    const cl = this.element().classList;
     if (bool === undefined)
       return cl.contains("no-more");
     else if (bool)
@@ -106,7 +109,7 @@
       return this._element;
     
     // Create list item
-    var li = document.createElement("li");
+    const li = document.createElement("li");
 
     // Connect action
     if (this["onclick"] !== undefined) {
@@ -135,14 +138,15 @@
       this.lowlight();
     }
 
-    var children = this.element().childNodes;
-    for (var i = children.length -1; i >= 0; i--) {
+    const children = this.element().childNodes;
+    for (let i = children.length -1; i >= 0; i--) {
       this._highlight(children[i], prefix);
     };
 
     this._prefix = prefix;
   },
 
+
   /**
    * Remove highlight of the menu item
    */
@@ -150,18 +154,18 @@
     if (this._prefix === null)
       return;
 
-    var e = this.element();
+    const e = this.element();
     
-    var marks = e.getElementsByTagName("mark");
-    for (var i = marks.length - 1; i >= 0; i--) {
-      // Create text node clone
-      var x = document.createTextNode(
-	      marks[i].firstChild.nodeValue
-      );
-      
+    const marks = e.getElementsByTagName("mark");
+
+    for (let i = marks.length - 1; i >= 0; i--) {
+
       // Replace with content
       marks[i].parentNode.replaceChild(
-	      x,
+        // Create text node clone
+	      document.createTextNode(
+	        marks[i].firstChild.nodeValue
+        ),
 	      marks[i]
       );
     };
@@ -176,8 +180,8 @@
   _highlight : function (elem, prefixString) {    
     if (elem.nodeType === 3) {
       
-      var text   = elem.nodeValue;
-      var textlc = text.toLowerCase();
+      const text   = elem.nodeValue;
+      const textlc = text.toLowerCase();
 
       // Split prefixes
       if (prefixString) {
@@ -186,12 +190,12 @@
         //   Doing this in a single line can trigger
         //   a deep-recursion in Firefox 57.01, though I don't know why.
         prefixString = prefixString.trim();
-        var prefixes = prefixString.split(" ");
 
-        var prefix;
-        var testPos;
-        var pos = -1;
-        var len = 0;
+        const prefixes = prefixString.split(" ");
+
+        let testPos,
+            pos = -1,
+            len = 0;
 
         // Iterate over all prefixes and get the best one
         // for (var i = 0; i < prefixes.length; i++) {
@@ -223,17 +227,17 @@
 	        };
 	
 	        // Second element
-	        var hl = document.createElement("mark");
+	        const hl = document.createElement("mark");
 	        hl.appendChild(
 	          document.createTextNode(text.substr(pos, len))
 	        );
 	        elem.parentNode.insertBefore(hl, elem);
 	
 	        // Third element
-	        var third = text.substr(pos + len);
+	        const third = text.substr(pos + len);
 
 	        if (third.length > 0) {
-	          var thirdE = document.createTextNode(third);
+	          const thirdE = document.createTextNode(third);
 	          elem.parentNode.insertBefore(
 	            thirdE,
 	            elem
@@ -241,14 +245,14 @@
 	          this._highlight(thirdE, prefixString);
 	        };
 	
-	        var p = elem.parentNode;
-	        p.removeChild(elem);
+          elem.parentNode.removeChild(elem);
         };
       };
     }
+
     else {
-      var children = elem.childNodes;
-      for (var i = children.length -1; i >= 0; i--) {
+      const children = elem.childNodes;
+      for (let i = children.length -1; i >= 0; i--) {
 	      this._highlight(children[i], prefixString);
       };
     };
@@ -261,17 +265,19 @@
       throw new Error("Missing parameters");
     };
 
-    this.content(params[0]);
+    const t = this;
+
+    t.content(params[0]);
     
     if (params.length > 1) {
-      this._action = params[1];
+      t._action = params[1];
 
       if (params.length > 2)
-        this._onclick = params[2];
+        t._onclick = params[2];
     };
     
-    this._lcField = ' ' + this.content().textContent.toLowerCase();
-    this._prefix = null;
+    t._lcField = ' ' + t.content().textContent.toLowerCase();
+    t._prefix = null;
 
     return this;
   },
@@ -281,7 +287,7 @@
    * The click action of the menu item.
    */
   onclick : function (e) {
-    var m = this.menu();
+    const m = this.menu();
 
     // Reset prefix
     m.prefix("");
diff --git a/dev/js/src/menu/lengthField.js b/dev/js/src/menu/lengthField.js
index 870d5ba..8a6641d 100644
--- a/dev/js/src/menu/lengthField.js
+++ b/dev/js/src/menu/lengthField.js
@@ -1,3 +1,5 @@
+"use strict";
+
 define({
 
   /**
@@ -7,6 +9,7 @@
     return Object.create(this)._init();
   },
 
+
   // Initialize lengthField object
   _init : function () {
     this._element = document.createElement('div');
@@ -14,6 +17,7 @@
     return this;
   },
 
+
   /**
    * Upgrade this object to another object,
    * while private data stays intact.
@@ -21,12 +25,13 @@
    * @param {Object} An object with properties.
    */
   upgradeTo : function (props) {
-    for (var prop in props) {
+    for (let prop in props) {
       this[prop] = props[prop];
     };
     return this;
   },
 
+
   /**
    * Get the associated dom element.
    */
@@ -34,6 +39,7 @@
     return this._element;
   },
 
+
   /**
    * Add string to lengthField.
    */
@@ -42,6 +48,7 @@
       .appendChild(document.createTextNode(param[0] + '--'));
   },
 
+
   /**
    * Remove all initialized values
    */
diff --git a/dev/js/src/menu/prefix.js b/dev/js/src/menu/prefix.js
index 90924c9..e513e85 100644
--- a/dev/js/src/menu/prefix.js
+++ b/dev/js/src/menu/prefix.js
@@ -1,3 +1,5 @@
+"use strict";
+
 define({
 
   /**
@@ -7,26 +9,31 @@
     return Object.create(this)._init();
   },
 
+
   // Initialize prefix object
   _init : function () {
-    this._string = '';
+    const t = this;
+
+    t._string = '';
 
     // Add prefix span
-    this._element = document.createElement('span');
-    this._element.classList.add('pref');
+    t._element = document.createElement('span');
+    t._element.classList.add('pref');
     // Connect action
 
-    if (this["onclick"] !== undefined)
-      this._element["onclick"] = this.onclick.bind(this);
+    if (t["onclick"] !== undefined)
+      t._element["onclick"] = t.onclick.bind(t);
     
-    return this;
+    return t;
   },
 
+
   _update : function () {
     return this._element.innerHTML
       = this._string;
   },
 
+
   /**
    * Upgrade this object to another object,
    * while private data stays intact.
@@ -34,7 +41,7 @@
    * @param {Object} An object with properties.
    */
   upgradeTo : function (props) {
-    for (var prop in props) {
+    for (let prop in props) {
       this[prop] = props[prop];
     };
     return this;
@@ -45,7 +52,7 @@
    * Get or set the activity status of the prefix.
    */
   active : function (bool) {
-    var cl = this.element().classList;
+    const cl = this.element().classList;
     if (bool === undefined)
       return cl.contains("active");
     else if (bool)
@@ -54,6 +61,7 @@
       cl.remove("active");
   },
 
+
   /**
    * Check, if a prefix is given or not.
    */
@@ -62,6 +70,7 @@
       true : false;
   },
 
+
   /**
    * Get or set the prefix string.
    */
@@ -81,7 +90,7 @@
     this._string += string;
     return this._update();
   },
-
+  
 
   /**
    * Clear prefix
@@ -98,23 +107,24 @@
    */
   onclick : function () {},
 
-
+  
   /**
    * Remove the last character of the string
    */
   chop : function () {
+    const t = this;
 
     // Prefix is long enough for backspace
-    if (this._string.length > 1) {
-      this._string = this._string.substring(
-	      0, this._string.length - 1
+    if (t._string.length > 1) {
+      t._string = t._string.substring(
+	      0, t._string.length - 1
       );
     }
     else {
-      this._string = '';
+      t._string = '';
     };
     
-    return this._update();
+    return t._update();
   },
 
 
diff --git a/dev/js/src/menu/slider.js b/dev/js/src/menu/slider.js
index adaf81a..5897da2 100644
--- a/dev/js/src/menu/slider.js
+++ b/dev/js/src/menu/slider.js
@@ -1,3 +1,5 @@
+"use strict";
+
 /**
  * Create slider for menus.
  * The slider will only be used by mouse - touch support
@@ -79,11 +81,11 @@
   movetoRel : function (relativePos) {
 
     // This is important to find the correct percentage!
-    var diffHeight = (this._rulerHeight - this._sliderHeight);
-    var relativeOffset = (relativePos / diffHeight);
+    const diffHeight = (this._rulerHeight - this._sliderHeight);
+    const relativeOffset = (relativePos / diffHeight);
 
     // Offset is a value 0 to this._screens
-    var off = this.offset(
+    const off = this.offset(
       parseInt(relativeOffset * this._screens) + this._event.initOffset
     );
 
@@ -99,9 +101,9 @@
    * @param {number} absolute position
    */
   movetoAbs : function (absPos) {
-    var absOffset = (absPos / this._rulerHeight);
+    const absOffset = (absPos / this._rulerHeight);
+    const off = this.offset(parseInt(absOffset * (this._screens + 1)));
 
-    var off = this.offset(parseInt(absOffset * (this._screens + 1)));
     if (off !== undefined) {
       this._menu.screen(off);
     };
@@ -148,10 +150,11 @@
    */
   reInit : function () {
 
-    var s = this._element.style;
+    const t = this;
+    const s = t._element.style;
 
     // Do not show the slider, in case there is nothing to scroll
-    if (this._length <= this._limit) {
+    if (t._length <= t._limit) {
       s.display = 'none';
       return;
     }
@@ -159,42 +162,43 @@
       s.display = 'block';
     };
 
-    this._height  = ((this._limit / this._length) * 100);
-    this._screens = this._length - this._limit;
-    this._step    = (100 - this._height) / this._screens;
-    this._slider.style.height = this._height + '%';
+    t._height  = ((t._limit / t._length) * 100);
+    t._screens = t._length - t._limit;
+    t._step    = (100 - t._height) / t._screens;
+    t._slider.style.height = t._height + '%';
   },
 
 
   // Initialize prefix object
   _init : function (menu) {
+    const t = this;
 
-    this._menu = menu;
+    t._menu = menu;
 
-    this._offset = 0;
-    this._event = {};
-    this._active = false;
+    t._offset = 0;
+    t._event = {};
+    t._active = false;
 
-    var el = this._element = document.createElement('div');
+    const el = t._element = document.createElement('div');
     el.setAttribute('class', 'ruler');
 
-    this._slider = el.appendChild(
+    t._slider = el.appendChild(
       document.createElement('span')
     );
 
-    this._ruler = el.appendChild(document.createElement('div'));
+    t._ruler = el.appendChild(document.createElement('div'));
 
     // Do not mark the menu on mousedown
-    this._ruler.addEventListener('mousedown', function (e) {
+    t._ruler.addEventListener('mousedown', function (e) {
       e.halt()
     }, false);
 
     // Move the slider to the click position
-    this._ruler.addEventListener('click', this._mouseclick.bind(this), false);
+    t._ruler.addEventListener('click', t._mouseclick.bind(t), false);
 
-    this._slider.addEventListener('mousedown', this._mousedown.bind(this), false);
+    t._slider.addEventListener('mousedown', t._mousedown.bind(t), false);
 
-    return this;
+    return t;
   },
 
 
@@ -224,7 +228,7 @@
   // Release mousedown event
   _mousedown : function (e) {
     // Bind drag handler
-    var ev = this._event;
+    const ev = this._event;
 
     // _step * _offset is the distance of the ruler to the top
     ev.init = e.clientY;