Modify editamolecule to load GWT scripts dynamically

common/lib/capa/capa/templates/editamolecule.html

 <section id="editamoleculeinput_${id}" class="editamoleculeinput">
-  <div class="script_placeholder" data-src="/static/js/capa/jsmolcalc/jsmolcalc.nocache.js"/>
-  <div class="script_placeholder" data-src="/static/js/capa/jsme/jsme_export.nocache.js"/>
   <div class="script_placeholder" data-src="${applet_loader}"/>
 
   % if status == 'unsubmitted':

common/static/js/capa/editamolecule.js

@@ -2,23 +2,53 @@
     var timeout = 100;
 
     // Simple "lock" to prevent applets from being initialized more than once
-    if (typeof(_editamolecule_lock) == 'undefined' || _editamolecule_lock == false) {
-        _editamolecule_lock = true;
+    if (typeof(_editamolecule_loaded) == 'undefined') {
+        _editamolecule_loaded = true;
+        loadGWTScripts();
         waitForGWT();
     } else {
         return;
     }
 
-    // FIXME: [rocha] jsme and jsmolcalc are not initialized automatically by
-    // the GWT script loader. To fix this, wait for the scripts to load, initialize
-    // them manually and wait until they are ready
+    function loadScript(src) {
+        var script = document.createElement('script');
+        script.setAttribute('type', 'text/javascript');
+        script.setAttribute('src',  src);
+        $('head')[0].appendChild(script);
+    }
+
+    function loadGWTScripts() {
+        // The names of the script are split to prevent them from
+        // being rewritten by LMS. GWT uses the filename of the script
+        // to find the URL path in which the script lives. If the name
+        // of the file is changed, GWT won't load correctly
+        var jsmolcalc_src = '/sta' + 'tic/js/capa/jsmolcalc/jsmolcalc.nocache.js';
+        var jsme_src = '/sta' + 'tic/js/capa/jsme/jsme_export.nocache.js';
+
+        // Make sure we don't request the scripts twice
+
+        if (typeof (_jsmolcalc) == 'undefined') {
+            _jsmolcalc = true;
+            loadScript(jsmolcalc_src);
+        }
+
+        if (typeof (_jsme) == 'undefined') {
+            _jsme = true;
+            loadScript(jsme_src);
+        }
+    }
+
     function waitForGWT() {
-        if (typeof(jsmolcalc) != "undefined" && jsmolcalc)
+        // jsme and jsmolcalc are not initialized automatically by the GWT
+        // script loader. To fix this, wait for the scripts to load,
+        // initialize them manually and wait until they are ready
+
+        if (typeof(jsmolcalc) != 'undefined' && jsmolcalc)
         {
             jsmolcalc.onInjectionDone('jsmolcalc');
         }
 
-        if (typeof(jsme_export) != "undefined" && jsme_export)
+        if (typeof(jsme_export) != 'undefined' && jsme_export)
         {
             // dummy function called by jsme_export
             window.jsmeOnLoad  = function() {};
@@ -29,7 +59,7 @@
         if (typeof(jsmol) != 'undefined' && typeof(JavaScriptApplet) != 'undefined') {
             // ready, initialize applets
             initializeApplets();
-            _editamolecule_lock = false;  // release lock, for reloading
+            _editamolecule_loaded = false;
         } else {
             setTimeout(waitForGWT, timeout);
         }
@@ -59,7 +89,6 @@
         var reset_button = parent.find('button.reset');
 
         // Add div for error messages
-        
         $('<br/> <br/> <div class="errormsgs" style="padding: 5px 5px 5px 5px;\
                 visibility:hidden; background-color:#FA6666; height:60px;\
                 width:400px;"> </div>').appendTo(parent);
@@ -93,16 +122,14 @@
 
     function requestAppletData(element, applet, input_field) {
         var molFile = $(element).data('molfile-src');
-
         jQuery.ajax({
             url: molFile,
             dataType: "text",
             success: function(data) {
-                //console.log("Done.");
                 loadAppletData(applet, data, input_field);
             },
             error: function() {
-                console.error("Cannot load mol data.");
+                console.error("Cannot load mol data from: " + molFile);
             }
         });
     }
@@ -118,12 +145,9 @@
         var jme = applet.jmeFile();
 
         var info = formatInfo(jsmol.API.getInfo(mol, smiles, jme).toString(),
-                input_field, element); 
+                input_field, element);
         var value = { mol: mol, info: info };
 
-        //console.log("Molecule info:");
-        //console.log(info);
-
         input_field.val(JSON.stringify(value));
 
         return value;
@@ -131,10 +155,8 @@
 
     function formatInfo(info, input_field, element) {
         var results = [];
-        //console.log("element parent is"+$(element).parent())
         var errordiv = $(element).parent().find('.errormsgs')[0];
-        //console.log(errordiv);
-        
+
         if (!errordiv) {
             // This is a bit hackish, but works.
             // There are situations where formatInfo is called but no div yet exists
@@ -143,7 +165,7 @@
             //console.log("There is no errordiv loaded yet. trying again soon");
             return []
         }
-        
+
         if (info.search("It is not possible") == -1) {
             errordiv.innerHTML = '';
             errordiv.style.visibility = 'hidden';
@@ -153,12 +175,10 @@
             });
         }
         else {
-            //console.log("err");
-
             // remove Brian's html tags
             var tags = /<((\/)?\w{1,7})>/g;
             var errmsg = info.replace(tags, ' ');
-            //console.log(errmsg);
+
             errordiv.innerHTML = errmsg;
             errordiv.style.visibility = 'visible';
         }