worksheet theme waits for document ready before init

The base start-exam.js used to use jQuery's load function to wait for the document to be loaded before doing the init stuff.

The worksheet theme didn't do anything, so there could be a timing problem if the code ran before the page had finished loading.

This adds a function Numbas.util.document_ready, which uses the native document.readyState property to wait until the page has finished loading, and changes both versions of start-exam.js to use it.

runtime/scripts/start-exam.js

@@ -14,7 +14,7 @@ Copyright 2011-14 Newcastle University
 // 'base' gives the third-party libraries on which Numbas depends
 Numbas.queueScript('base',['jquery','localisation','seedrandom','knockout','sarissa'],function() {
 });
-Numbas.queueScript('start-exam',['base','exam','settings'],function() {
+Numbas.queueScript('start-exam',['base','util', 'exam','settings'],function() {
     for(var name in Numbas.custom_part_types) {
         Numbas.partConstructors[name] = Numbas.parts.CustomPart;
     };
@@ -43,7 +43,7 @@ Numbas.queueScript('start-exam',['base','exam','settings'],function() {
      * @function
      */
     var init = Numbas.init = function() {
-        $(document).ready(function() {
+        Numbas.util.document_ready(function() {
             for(var x in Numbas.extensions) {
                 Numbas.activateExtension(x);
             }

runtime/scripts/util.js

@@ -14,6 +14,22 @@ Copyright 2011-14 Newcastle University
 Numbas.queueScript('util',['base', 'math', 'parsel'],function() {
 /** @namespace Numbas.util */
 var util = Numbas.util = /** @lends Numbas.util */ {
+    /** Run the given function when the document is ready.
+     *
+     * @param {Function} fn
+     */
+    document_ready: function(fn) {
+        if(document.readyState == 'complete') {
+            setTimeout(fn, 1);
+        } else {
+            document.addEventListener('readystatechange', function(e) {
+                if(document.readyState == 'complete') {
+                    setTimeout(fn, 1);
+                }
+            });
+        }
+    },
+
     /** Derive type B from A (class inheritance, really)
      *
      * B's prototype supercedes A's.

themes/worksheet/files/scripts/start-exam.js

@@ -1,25 +1,27 @@
-// 'base' gives the third-party libraries on which Numbas depends
-Numbas.queueScript('base',['jquery','localisation','seedrandom','knockout','sarissa'],function() {
-});
-
-
-Numbas.queueScript('start-exam',['base','exam','settings'],function() {
-    for(var name in Numbas.custom_part_types) {
-        Numbas.partConstructors[name] = Numbas.parts.CustomPart;
-    };
-
-	Numbas.init = function() {
-        for(var x in Numbas.extensions) {
-            Numbas.activateExtension(x);
-        }
-		var job = Numbas.schedule.add;
-
-		job(Numbas.xml.loadXMLDocs);				//load in all the XML and XSLT files
-
-		job(function() {
-			var store = Numbas.store = new Numbas.storage.scorm.SCORMStorage();	//The storage object manages communication between the LMS and the exam
-			Numbas.display.init();
-		});
-	};
-});
-
+// 'base' gives the third-party libraries on which Numbas depends
+Numbas.queueScript('base',['jquery','localisation','seedrandom','knockout','sarissa'],function() {
+});
+
+
+Numbas.queueScript('start-exam',['base','exam','settings'],function() {
+    for(var name in Numbas.custom_part_types) {
+        Numbas.partConstructors[name] = Numbas.parts.CustomPart;
+    };
+
+	Numbas.init = function() {
+        Numbas.util.document_ready(function() {
+            for(var x in Numbas.extensions) {
+                Numbas.activateExtension(x);
+            }
+            var job = Numbas.schedule.add;
+
+            job(Numbas.xml.loadXMLDocs);				//load in all the XML and XSLT files
+
+            job(function() {
+                var store = Numbas.store = new Numbas.storage.scorm.SCORMStorage();	//The storage object manages communication between the LMS and the exam
+                Numbas.display.init();
+            });
+        });
+	};
+});
+