Fixed issue #05679: Questions conditional upon previous questions do …

…not appear until "Next" button is pressed

Dev core problem was uncaught javascript errors when processing relevance of hidden questions

git-svn-id: file:///Users/Shitiz/Downloads/lssvn/source/limesurvey_dev@12248 b72ed6b6-b9f8-46b5-92b4-906544132732

classes/eval/em_javascript.js

@@ -234,6 +234,7 @@ function LEMval(alias)
     }
     if (whichJsName === null || typeof document.getElementById(whichJsName) === 'undefined' || document.getElementById(whichJsName) === null) {
         an_error = true;    // this line is here to make debugging easier
+        return '';
     }
 
     // values should always be stored encoded with htmlspecialchars()