diff --git a/dev/js/src/init.js b/dev/js/src/init.js
index b9822fd..f7a136c 100644
--- a/dev/js/src/init.js
+++ b/dev/js/src/init.js
@@ -359,9 +359,15 @@
 // Render Virtual collection
 function _getCurrentVC (vcClass, vcArray) {
   var vc = vcClass.create(vcArray);
-  if (KorAP.koralQuery !== undefined && KorAP.koralQuery["collection"]) {
-    vc.fromJson(KorAP.koralQuery["collection"]);
-  };
+  try {
+    if (KorAP.koralQuery !== undefined && KorAP.koralQuery["collection"]) {
+      vc.fromJson(KorAP.koralQuery["collection"]);
+    };
+  }
+  catch (e) {
+    KorAP.log(0, e);
+    return;
+  }
   return vc;
 };
 
diff --git a/dev/js/src/vc.js b/dev/js/src/vc.js
index 527e116..8a5c6b8 100644
--- a/dev/js/src/vc.js
+++ b/dev/js/src/vc.js
@@ -316,18 +316,9 @@
           var that = this;
           var actions = panel.actions;
           var statView;
-          
-          //delete log after solving the cq= -Problem.
-          console.log("vc._root.element() = " + that._root.element().innerHTML);
-          console.log("vc._root.toQuery = " + that._root.toQuery());
-          
+                    
           actions.add(loc.SHOW_STAT, [ 'statistic' ], function() {
             if (statView === undefined || !statView.shown()) {
-             
-              //delete log after solving the cq= -Problem
-              console.log("statView created mit vc.toQuery()= "
-                  + that.toQuery());
-             
               statView = corpStatVClass.create(that);
               panel.add(statView);
             }
diff --git a/dev/js/src/vc/doc.js b/dev/js/src/vc/doc.js
index d2a413e..15c7287 100644
--- a/dev/js/src/vc/doc.js
+++ b/dev/js/src/vc/doc.js
@@ -9,8 +9,14 @@
   'util'
 ], function (jsonldClass, rewriteListClass, stringValClass) {
 
+  /*
+   * TODO:
+   *   Improve error handling by using window.onerror() to
+   *   capture thrown errors and log them.
+   */
 
   const errstr802 = "Match type is not supported by value type";
+  const errstr804 = "Unknown value type";
   const loc = KorAP.Locale;
   loc.EMPTY = loc.EMPTY || '⋯';
 
@@ -319,8 +325,8 @@
         }
 
         else {
-          KorAP.log(804, "Unknown value type");
-          return;
+          KorAP.log(804, errstr804 + ": " + this.type());
+          throw new Error(errstr804 + ": " + this.type());
         };
       };
 
@@ -622,13 +628,11 @@
       switch (this.type()) {
       case "date":
         return string + this.value();
-        break;
       case "regex":
         return string + '/' + this.value().escapeRegex() + '/';
-        break;
       case "string":
+      case "text":
         return string + '"' + this.value().quote() + '"';
-        break;
       };
 
       return "";