public/js/src/menu.js - KorAP/Kalamar - Gitiles

 var KorAP = KorAP || {};

 /**
  * Create scrollable drop-down menus.
  *
  * @author Nils Diewald
  */

 (function (KorAP) {
   "use strict";

   // Don't let events bubble up
   Event.prototype.halt = function () {
     this.stopPropagation();
     this.preventDefault();
   };

   // Default maximum number of menu items
   KorAP.menuLimit = 8;

   /**
    * List of items for drop down menu (complete).
    * Only a sublist of the menu is filtered (live).
    * Only a sublist of the filtered menu is visible (shown).
    */
   KorAP.Menu = {
     /**
      * Create new Menu based on the action prefix
      * and a list of menu items.
      *
      * @this {Menu}
      * @constructor
      * @param {string} Context prefix
      * @param {Array.<Array.<string>>} List of menu items
      */
     create : function (params) {
       return Object.create(KorAP.Menu)._init(params);
     },

     focus : function () {
       this._element.focus();
     },

     // mouse wheel treatment
     _mousewheel : function (e) {
       var delta = 0;
       if (e.wheelDelta) {
 	delta = event.wheelDelta / 120;
       }
       else if (e.detail) {
 	delta = - e.detail / 3;
       };
       if (delta < 0) {
 	this.next();
       }
       else {
 	this.prev();
       };
       e.halt();
     },

     // Arrow key and prefix treatment
     _keydown : function (e) {
       var code = _codeFromEvent(e);

       /*
        * keyCodes:
        * - Down  = 40
        * - Esc   = 27
        * - Up    = 38
        * - Enter = 13
        * - shift = 16
        * for characters use e.key
        */

       switch (code) {
       case 27: // 'Esc'
 	e.halt();
 	this.hide();
 	break;
       case 40: // 'Down'
 	e.halt();
 	this.next();
 	break;
       case 38: // 'Up'
 	e.halt();
 	this.prev();
 	break;
       case 13: // 'Enter'
 	console.log('hide');
 	e.halt();
 	this.hide();
 	break;
       case 8: // 'Backspace'
 	var p = this.prefix();
 	if (p.length > 1) {
 	  p = p.substring(0, p.length - 1)
 	  this.show(p);
 	}
 	else {
 	  this.show();
 	};
 	e.halt();
 	break;
       default:
 	if (e.key !== undefined && e.key.length != 1)
 	  return;

 	// Add prefix
 	if (!this.show(this.prefix() + e.key))
 	  this.hide();
       };
     },

     // Initialize list
     _init : function (itemClass, params) {
       // this._element.addEventListener("click", chooseHint, false);
       var that = this;
       this._itemClass = itemClass;
       var e =this._element = document.createElement("ul");
       e.style.opacity = 0;
       e.style.outline = 0;
       e.setAttribute('tabindex', 0);

       // Arrow keys
       e.addEventListener(
 	"keydown",
 	function (ev) {
 	  that._keydown(ev)
 	},
 	false
       );

       // Mousewheel
       e.addEventListener(
 	'DOMMouseScroll',
 	function (ev) {
 	  that._mousewheel(ev)
 	},
 	false
       );

       this.active = false;
       this._items = new Array();
       var i;

       // Initialize item list based on parameters
       for (i in params) {
 	var obj = itemClass.create(params[i]);
 	this._items.push(obj);
       };
       this._limit    = KorAP.menuLimit;
       this._position = 0;  // position in the active list
       this._active   = -1; // active item in the item list
       this._reset();
       return this;
     },

     /**
      * Get the instantiated HTML element
      */
     element : function () {
       return this._element;
     },

     /**
      * Get the creator object for items
      */
     itemClass : function () {
       return this._itemClass;
     },

     /**
      * Get and set numerical value for limit,
      * i.e. the number of items visible.
      */
     limit : function (limit) {
       if (arguments.length === 1)
 	this._limit = limit;
       return this._limit;
     },

     /**
      * Upgrade this object to another object,
      * while private data stays intact.
      *
      * @param {Object} An object with properties.
      */
     upgradeTo : function (props) {
       for (var prop in props) {
 	this[prop] = props[prop];
       };
       return this;
     },

     // Reset chosen item and prefix
     _reset : function () {
       this._offset = 0;
       this._pos    = 0;
       this._prefix = undefined;
     },

     /**
      * Filter the list and make it visible
      *
      * @param {string} Prefix for filtering the list
      */
     show : function (prefix) {
       this._prefix = prefix;

       // Initialize the list
       if (!this._initList())
 	return false;

       // show based on initial offset
       this._showItems(0);

       // Set the first element to active
       // Todo: Or the last element chosen
       this.liveItem(0).active(true);

       this._position = 0;
       this._active = this._list[0];

       this._element.style.opacity = 1;

       // Add classes for rolling menus
       this._boundary(true);
       return true;
     },

     hide : function () {
       this.active = false;
       this.delete();
       this._element.style.opacity = 0;

 /*
       this._element.blur();
 */
     },

     // Initialize the list
     _initList : function () {

       // Create a new list
       if (this._list === undefined) {
 	this._list = [];
       }
       else if (this._list.length != 0) {
 	this._boundary(false);
 	this._list.length = 0;
       };

       // Offset is initially zero
       this._offset = 0;

       // There is no prefix set
       if (this.prefix().length <= 0) {
 	for (var i = 0; i < this._items.length; i++)
 	  this._list.push(i);
 	return true;
       };

       // There is a prefix set, so filter the list
       var pos;
       var paddedPrefix = " " + this.prefix();

       // Iterate over all items and choose preferred matching items
       // i.e. the matching happens at the word start
       for (pos = 0; pos < this._items.length; pos++) {
 	if ((this.item(pos).lcField().indexOf(paddedPrefix)) >= 0)
 	  this._list.push(pos);
       };

       // 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
       if (this._list.length == 0) {
 	for (pos = 0; pos < this._items.length; pos++) {
 	  if ((this.item(pos).lcField().indexOf(this.prefix())) >= 0)
 	    this._list.push(pos);
 	};
       };

       // Filter was successful - yeah!
       return this._list.length > 0 ? true : false;
     },

     // Set boundary for viewport
     _boundary : function (bool) {
       this.item(this._list[0]).noMore(bool);
       this.item(this._list[this._list.length - 1]).noMore(bool);
     },

     /**
      * Get the prefix for filtering,
      * e.g. &quot;ve&quot; for &quot;verb&quot;
      */
     prefix : function () {
       return this._prefix || '';
     },

     // Append Items that should be shown
     _showItems : function (offset) {
       this.delete();

       // Use list
       var shown = 0;
       var i;
       for (i in this._list) {

 	// Don't show - it's before offset
 	if (shown++ < offset)
 	  continue;

 	this._append(this._list[i]);

 	if (shown >= (this.limit() + this._offset))
 	  break;
       };
     },

     /**
      * Delete all visible items from the menu element
      */
     delete : function () {
       var child;

       // Iterate over all visible items
       for (var i = 0; i <= this.limit(); i++) {

 	// there is a visible element - unhighlight!
 	if (child = this.shownItem(i)) {
 	  child.lowlight();
 	  child.active(false);
 	};
       };

       // Remove all children
       while (child = this._element.firstChild)
 	this._element.removeChild(child);
     },


     // Append item to the shown list based on index
     _append : function (i) {
       var item = this.item(i);

       // Highlight based on prefix
       if (this.prefix().length > 0)
 	item.highlight(this.prefix());

       // Append element
       this.element().appendChild(item.element());
     },


     // Prepend item to the shown list based on index
     _prepend : function (i) {
       var item = this.item(i);

       // Highlight based on prefix
       if (this.prefix().length > 0)
 	item.highlight(this.prefix());

       var e = this.element();
       // Append element
       e.insertBefore(
 	item.element(),
 	e.firstChild
       );
     },


     /**
      * Get a specific item from the complete list
      *
      * @param {number} index of the list item
      */
     item : function (index) {
       return this._items[index]
     },


     /**
      * Get a specific item from the filtered list
      *
      * @param {number} index of the list item
      *        in the filtered list
      */
     liveItem : function (index) {
       if (this._list === undefined)
 	if (!this._initList())
 	  return;

       return this._items[this._list[index]];
     },


     /**
      * Get a specific item from the visible list
      *
      * @param {number} index of the list item
      *        in the visible list
      */
     shownItem : function (index) {
       if (index >= this.limit())
 	return;
       return this.liveItem(this._offset + index);
     },


     /**
      * Get the length of the full list
      */
     length : function () {
       return this._items.length;
     },


     /**
      * Make the next item in the filtered menu active
      */
     next : function () {
       // No active element set
       if (this._position == -1)
 	return;

       // Set new live item
       var oldItem = this.liveItem(this._position++);
       oldItem.active(false);
       var newItem = this.liveItem(this._position);

       // The next element is undefined - roll to top
       if (newItem === undefined) {
 	this._offset = 0;
 	this._position = 0;
 	newItem = this.liveItem(0);
 	this._showItems(0);
       }

       // The next element is outside the view - roll down
       else if (this._position >= (this.limit() + this._offset)) {
 	this._removeFirst();
 	this._offset++;
 	this._append(this._list[this._position]);
       };
       newItem.active(true);
     },


     /*
      * Make the previous item in the menu active
      */
     prev : function () {
       // No active element set
       if (this._position == -1)
 	return;

       // Set new live item
       var oldItem = this.liveItem(this._position--);
       oldItem.active(false);
       var newItem = this.liveItem(this._position);

       // The previous element is undefined - roll to bottom
       if (newItem === undefined) {
 	this._offset = this.liveLength() - this.limit();
 	this._position = this.liveLength() - 1;
 	newItem = this.liveItem(this._position);
 	this._showItems(this._offset);
       }

       // The previous element is outside the view - roll up
       else if (this._position < this._offset) {
 	this._removeLast();
 	this._offset--;
 	this._prepend(this._list[this._position]);
       };

       newItem.active(true);
     },


     // Remove the HTML node from the first item
     _removeFirst : function () {
       this.item(this._list[this._offset]).lowlight();
       this._element.removeChild(this._element.firstChild);
     },


     // Remove the HTML node from the last item
     _removeLast : function () {
       this.item(this._list[this._offset + this.limit() - 1]).lowlight();
       this._element.removeChild(this._element.lastChild);
     },

     // Length of the filtered list
     liveLength : function () {
       if (this._list === undefined)
 	this._initList();
       return this._list.length;
     }
   };


   /**
    * Item in the Dropdown menu
    */
   KorAP.MenuItem = {

     /**
      * Create a new MenuItem object.
      *
      * @constructor
      * @this {MenuItem}
      * @param {Array.<string>} An array object of name, action and
      *   optionally a description
      */
     create : function (params) {
       return Object.create(KorAP.MenuItem)._init(params);
     },

     /**
      * Upgrade this object to another object,
      * while private data stays intact.
      *
      * @param {Object] An object with properties.
      */
     upgradeTo : function (props) {
       for (var prop in props) {
 	this[prop] = props[prop];
       };
       return this;
     },

     content : function (content) {
       if (arguments.length === 1)
 	this._content = document.createTextNode(content);
       return this._content;
     },

     lcField : function () {
       return this._lcField;
     },

     action : function (action) {
       if (arguments.length === 1)
 	this._action = action;
       return this._action;
     },

     /**
      * Check or set if the item is active
      *
      * @param {boolean|null} State of activity
      */
     active : function (bool) {
       var cl = this.element().classList;
       if (bool === undefined)
 	return cl.contains("active");
       else if (bool)
 	cl.add("active");
       else
 	cl.remove("active");
     },

     /**
      * Check or set if the item is
      * at the boundary of the menu
      * list
      *
      * @param {boolean|null} State of activity
      */
     noMore : function (bool) {
       var cl = this.element().classList;
       if (bool === undefined)
 	return cl.contains("no-more");
       else if (bool)
 	cl.add("no-more");
       else
 	cl.remove("no-more");
     },

     /**
      * Get the document element of the menu item
      */
     element : function () {
       // already defined
       if (this._element !== undefined)
 	return this._element;

       // Create list item
       var li = document.createElement("li");

       // Connect action
       li["action"] = this._action;

       // Append template
       li.appendChild(this.content());

       return this._element = li;
     },

     /**
      * Highlight parts of the item
      *
      * @param {string} Prefix string for highlights
      */
     highlight : function (prefix) {
       var children = this.element().childNodes;
       for (var i = children.length -1; i >= 0; i--) {
 	this._highlight(children[i], prefix);
       };
     },

     // Highlight a certain substring of the menu item
     _highlight : function (elem, prefix) {

       if (elem.nodeType === 3) {

 	var text   = elem.nodeValue;
 	var textlc = text.toLowerCase();
 	var pos    = textlc.indexOf(prefix);
 	if (pos >= 0) {

 	  // First element
 	  if (pos > 0) {
 	    elem.parentNode.insertBefore(
 	      document.createTextNode(text.substr(0, pos)),
 	      elem
 	    );
 	  };

 	  // Second element
 	  var hl = document.createElement("mark");
 	  hl.appendChild(
 	    document.createTextNode(text.substr(pos, prefix.length))
 	  );
 	  elem.parentNode.insertBefore(hl, elem);

 	  // Third element
 	  var third = text.substr(pos + prefix.length);
 	  if (third.length > 0) {
 	    var thirdE = document.createTextNode(third);
 	    elem.parentNode.insertBefore(
 	      thirdE,
 	      elem
 	    );
 	    this._highlight(thirdE, prefix);
 	  };

 	  var p = elem.parentNode;
 	  p.removeChild(elem);
 	};
       }
       else {
 	var children = elem.childNodes;
 	for (var i = children.length -1; i >= 0; i--) {
 	  this._highlight(children[i], prefix);
 	};
       };
     },


     /**
      * Remove highlight of the menu item
      */
     lowlight : function () {
       var 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
 	);

 	// Replace with content
 	marks[i].parentNode.replaceChild(
 	  x,
 	  marks[i]
 	);
       };

       // Remove consecutive textnodes
       e.normalize();
     },

     // Initialize menu item
     _init : function (params) {

       if (params[0] === undefined)
 	throw new Error("Missing parameters");

       this.content(params[0]);

       if (params.length === 2)
 	this._action = params[1];

       this._lcField = ' ' + this.content().textContent.toLowerCase();

       return this;
     },
   };

   function _codeFromEvent (e) {
     if ((e.charCode) && (e.keyCode==0))
       return e.charCode
     return e.keyCode;
   };

 }(this.KorAP));
	var KorAP = KorAP \|\| {};

	/**
	* Create scrollable drop-down menus.
	*
	* @author Nils Diewald
	*/

	(function (KorAP) {
	"use strict";

	// Don't let events bubble up
	Event.prototype.halt = function () {
	this.stopPropagation();
	this.preventDefault();
	};

	// Default maximum number of menu items
	KorAP.menuLimit = 8;

	/**
	* List of items for drop down menu (complete).
	* Only a sublist of the menu is filtered (live).
	* Only a sublist of the filtered menu is visible (shown).
	*/
	KorAP.Menu = {
	/**
	* Create new Menu based on the action prefix
	* and a list of menu items.
	*
	* @this {Menu}
	* @constructor
	* @param {string} Context prefix
	* @param {Array.<Array.<string>>} List of menu items
	*/
	create : function (params) {
	return Object.create(KorAP.Menu)._init(params);
	},

	focus : function () {
	this._element.focus();
	},

	// mouse wheel treatment
	_mousewheel : function (e) {
	var delta = 0;
	if (e.wheelDelta) {
	delta = event.wheelDelta / 120;
	}
	else if (e.detail) {
	delta = - e.detail / 3;
	};
	if (delta < 0) {
	this.next();
	}
	else {
	this.prev();
	};
	e.halt();
	},

	// Arrow key and prefix treatment
	_keydown : function (e) {
	var code = _codeFromEvent(e);

	/*
	* keyCodes:
	* - Down = 40
	* - Esc = 27
	* - Up = 38
	* - Enter = 13
	* - shift = 16
	* for characters use e.key
	*/

	switch (code) {
	case 27: // 'Esc'
	e.halt();
	this.hide();
	break;
	case 40: // 'Down'
	e.halt();
	this.next();
	break;
	case 38: // 'Up'
	e.halt();
	this.prev();
	break;
	case 13: // 'Enter'
	console.log('hide');
	e.halt();
	this.hide();
	break;
	case 8: // 'Backspace'
	var p = this.prefix();
	if (p.length > 1) {
	p = p.substring(0, p.length - 1)
	this.show(p);
	}
	else {
	this.show();
	};
	e.halt();
	break;
	default:
	if (e.key !== undefined && e.key.length != 1)
	return;

	// Add prefix
	if (!this.show(this.prefix() + e.key))
	this.hide();
	};
	},

	// Initialize list
	_init : function (itemClass, params) {
	// this._element.addEventListener("click", chooseHint, false);
	var that = this;
	this._itemClass = itemClass;
	var e =this._element = document.createElement("ul");
	e.style.opacity = 0;
	e.style.outline = 0;
	e.setAttribute('tabindex', 0);

	// Arrow keys
	e.addEventListener(
	"keydown",
	function (ev) {
	that._keydown(ev)
	},
	false
	);

	// Mousewheel
	e.addEventListener(
	'DOMMouseScroll',
	function (ev) {
	that._mousewheel(ev)
	},
	false
	);

	this.active = false;
	this._items = new Array();
	var i;

	// Initialize item list based on parameters
	for (i in params) {
	var obj = itemClass.create(params[i]);
	this._items.push(obj);
	};
	this._limit = KorAP.menuLimit;
	this._position = 0; // position in the active list
	this._active = -1; // active item in the item list
	this._reset();
	return this;
	},

	/**
	* Get the instantiated HTML element
	*/
	element : function () {
	return this._element;
	},

	/**
	* Get the creator object for items
	*/
	itemClass : function () {
	return this._itemClass;
	},

	/**
	* Get and set numerical value for limit,
	* i.e. the number of items visible.
	*/
	limit : function (limit) {
	if (arguments.length === 1)
	this._limit = limit;
	return this._limit;
	},

	/**
	* Upgrade this object to another object,
	* while private data stays intact.
	*
	* @param {Object} An object with properties.
	*/
	upgradeTo : function (props) {
	for (var prop in props) {
	this[prop] = props[prop];
	};
	return this;
	},

	// Reset chosen item and prefix
	_reset : function () {
	this._offset = 0;
	this._pos = 0;
	this._prefix = undefined;
	},

	/**
	* Filter the list and make it visible
	*
	* @param {string} Prefix for filtering the list
	*/
	show : function (prefix) {
	this._prefix = prefix;

	// Initialize the list
	if (!this._initList())
	return false;

	// show based on initial offset
	this._showItems(0);

	// Set the first element to active
	// Todo: Or the last element chosen
	this.liveItem(0).active(true);

	this._position = 0;
	this._active = this._list[0];

	this._element.style.opacity = 1;

	// Add classes for rolling menus
	this._boundary(true);
	return true;
	},

	hide : function () {
	this.active = false;
	this.delete();
	this._element.style.opacity = 0;

	/*
	this._element.blur();
	*/
	},

	// Initialize the list
	_initList : function () {

	// Create a new list
	if (this._list === undefined) {
	this._list = [];
	}
	else if (this._list.length != 0) {
	this._boundary(false);
	this._list.length = 0;
	};

	// Offset is initially zero
	this._offset = 0;

	// There is no prefix set
	if (this.prefix().length <= 0) {
	for (var i = 0; i < this._items.length; i++)
	this._list.push(i);
	return true;
	};

	// There is a prefix set, so filter the list
	var pos;
	var paddedPrefix = " " + this.prefix();

	// Iterate over all items and choose preferred matching items
	// i.e. the matching happens at the word start
	for (pos = 0; pos < this._items.length; pos++) {
	if ((this.item(pos).lcField().indexOf(paddedPrefix)) >= 0)
	this._list.push(pos);
	};

	// 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
	if (this._list.length == 0) {
	for (pos = 0; pos < this._items.length; pos++) {
	if ((this.item(pos).lcField().indexOf(this.prefix())) >= 0)
	this._list.push(pos);
	};
	};

	// Filter was successful - yeah!
	return this._list.length > 0 ? true : false;
	},

	// Set boundary for viewport
	_boundary : function (bool) {
	this.item(this._list[0]).noMore(bool);
	this.item(this._list[this._list.length - 1]).noMore(bool);
	},

	/**
	* Get the prefix for filtering,
	* e.g. "ve" for "verb"
	*/
	prefix : function () {
	return this._prefix \|\| '';
	},

	// Append Items that should be shown
	_showItems : function (offset) {
	this.delete();

	// Use list
	var shown = 0;
	var i;
	for (i in this._list) {

	// Don't show - it's before offset
	if (shown++ < offset)
	continue;

	this._append(this._list[i]);

	if (shown >= (this.limit() + this._offset))
	break;
	};
	},

	/**
	* Delete all visible items from the menu element
	*/
	delete : function () {
	var child;

	// Iterate over all visible items
	for (var i = 0; i <= this.limit(); i++) {

	// there is a visible element - unhighlight!
	if (child = this.shownItem(i)) {
	child.lowlight();
	child.active(false);
	};
	};

	// Remove all children
	while (child = this._element.firstChild)
	this._element.removeChild(child);
	},


	// Append item to the shown list based on index
	_append : function (i) {
	var item = this.item(i);

	// Highlight based on prefix
	if (this.prefix().length > 0)
	item.highlight(this.prefix());

	// Append element
	this.element().appendChild(item.element());
	},


	// Prepend item to the shown list based on index
	_prepend : function (i) {
	var item = this.item(i);

	// Highlight based on prefix
	if (this.prefix().length > 0)
	item.highlight(this.prefix());

	var e = this.element();
	// Append element
	e.insertBefore(
	item.element(),
	e.firstChild
	);
	},


	/**
	* Get a specific item from the complete list
	*
	* @param {number} index of the list item
	*/
	item : function (index) {
	return this._items[index]
	},


	/**
	* Get a specific item from the filtered list
	*
	* @param {number} index of the list item
	* in the filtered list
	*/
	liveItem : function (index) {
	if (this._list === undefined)
	if (!this._initList())
	return;

	return this._items[this._list[index]];
	},


	/**
	* Get a specific item from the visible list
	*
	* @param {number} index of the list item
	* in the visible list
	*/
	shownItem : function (index) {
	if (index >= this.limit())
	return;
	return this.liveItem(this._offset + index);
	},


	/**
	* Get the length of the full list
	*/
	length : function () {
	return this._items.length;
	},


	/**
	* Make the next item in the filtered menu active
	*/
	next : function () {
	// No active element set
	if (this._position == -1)
	return;

	// Set new live item
	var oldItem = this.liveItem(this._position++);
	oldItem.active(false);
	var newItem = this.liveItem(this._position);

	// The next element is undefined - roll to top
	if (newItem === undefined) {
	this._offset = 0;
	this._position = 0;
	newItem = this.liveItem(0);
	this._showItems(0);
	}

	// The next element is outside the view - roll down
	else if (this._position >= (this.limit() + this._offset)) {
	this._removeFirst();
	this._offset++;
	this._append(this._list[this._position]);
	};
	newItem.active(true);
	},


	/*
	* Make the previous item in the menu active
	*/
	prev : function () {
	// No active element set
	if (this._position == -1)
	return;

	// Set new live item
	var oldItem = this.liveItem(this._position--);
	oldItem.active(false);
	var newItem = this.liveItem(this._position);

	// The previous element is undefined - roll to bottom
	if (newItem === undefined) {
	this._offset = this.liveLength() - this.limit();
	this._position = this.liveLength() - 1;
	newItem = this.liveItem(this._position);
	this._showItems(this._offset);
	}

	// The previous element is outside the view - roll up
	else if (this._position < this._offset) {
	this._removeLast();
	this._offset--;
	this._prepend(this._list[this._position]);
	};

	newItem.active(true);
	},


	// Remove the HTML node from the first item
	_removeFirst : function () {
	this.item(this._list[this._offset]).lowlight();
	this._element.removeChild(this._element.firstChild);
	},


	// Remove the HTML node from the last item
	_removeLast : function () {
	this.item(this._list[this._offset + this.limit() - 1]).lowlight();
	this._element.removeChild(this._element.lastChild);
	},

	// Length of the filtered list
	liveLength : function () {
	if (this._list === undefined)
	this._initList();
	return this._list.length;
	}
	};


	/**
	* Item in the Dropdown menu
	*/
	KorAP.MenuItem = {

	/**
	* Create a new MenuItem object.
	*
	* @constructor
	* @this {MenuItem}
	* @param {Array.<string>} An array object of name, action and
	* optionally a description
	*/
	create : function (params) {
	return Object.create(KorAP.MenuItem)._init(params);
	},

	/**
	* Upgrade this object to another object,
	* while private data stays intact.
	*
	* @param {Object] An object with properties.
	*/
	upgradeTo : function (props) {
	for (var prop in props) {
	this[prop] = props[prop];
	};
	return this;
	},

	content : function (content) {
	if (arguments.length === 1)
	this._content = document.createTextNode(content);
	return this._content;
	},

	lcField : function () {
	return this._lcField;
	},

	action : function (action) {
	if (arguments.length === 1)
	this._action = action;
	return this._action;
	},

	/**
	* Check or set if the item is active
	*
	* @param {boolean\|null} State of activity
	*/
	active : function (bool) {
	var cl = this.element().classList;
	if (bool === undefined)
	return cl.contains("active");
	else if (bool)
	cl.add("active");
	else
	cl.remove("active");
	},

	/**
	* Check or set if the item is
	* at the boundary of the menu
	* list
	*
	* @param {boolean\|null} State of activity
	*/
	noMore : function (bool) {
	var cl = this.element().classList;
	if (bool === undefined)
	return cl.contains("no-more");
	else if (bool)
	cl.add("no-more");
	else
	cl.remove("no-more");
	},

	/**
	* Get the document element of the menu item
	*/
	element : function () {
	// already defined
	if (this._element !== undefined)
	return this._element;

	// Create list item
	var li = document.createElement("li");

	// Connect action
	li["action"] = this._action;

	// Append template
	li.appendChild(this.content());

	return this._element = li;
	},

	/**
	* Highlight parts of the item
	*
	* @param {string} Prefix string for highlights
	*/
	highlight : function (prefix) {
	var children = this.element().childNodes;
	for (var i = children.length -1; i >= 0; i--) {
	this._highlight(children[i], prefix);
	};
	},

	// Highlight a certain substring of the menu item
	_highlight : function (elem, prefix) {

	if (elem.nodeType === 3) {

	var text = elem.nodeValue;
	var textlc = text.toLowerCase();
	var pos = textlc.indexOf(prefix);
	if (pos >= 0) {

	// First element
	if (pos > 0) {
	elem.parentNode.insertBefore(
	document.createTextNode(text.substr(0, pos)),
	elem
	);
	};

	// Second element
	var hl = document.createElement("mark");
	hl.appendChild(
	document.createTextNode(text.substr(pos, prefix.length))
	);
	elem.parentNode.insertBefore(hl, elem);

	// Third element
	var third = text.substr(pos + prefix.length);
	if (third.length > 0) {
	var thirdE = document.createTextNode(third);
	elem.parentNode.insertBefore(
	thirdE,
	elem
	);
	this._highlight(thirdE, prefix);
	};

	var p = elem.parentNode;
	p.removeChild(elem);
	};
	}
	else {
	var children = elem.childNodes;
	for (var i = children.length -1; i >= 0; i--) {
	this._highlight(children[i], prefix);
	};
	};
	},


	/**
	* Remove highlight of the menu item
	*/
	lowlight : function () {
	var 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
	);

	// Replace with content
	marks[i].parentNode.replaceChild(
	x,
	marks[i]
	);
	};

	// Remove consecutive textnodes
	e.normalize();
	},

	// Initialize menu item
	_init : function (params) {

	if (params[0] === undefined)
	throw new Error("Missing parameters");

	this.content(params[0]);

	if (params.length === 2)
	this._action = params[1];

	this._lcField = ' ' + this.content().textContent.toLowerCase();

	return this;
	},
	};

	function _codeFromEvent (e) {
	if ((e.charCode) && (e.keyCode==0))
	return e.charCode
	return e.keyCode;
	};

	}(this.KorAP));