Merge branch 'MDL-57374_master' of https://github.com/dasistwas/moodle

lib/editor/atto/yui/src/editor/js/clean.js

@@ -147,9 +147,9 @@ EditorClean.prototype = {
                     isHTML = (types.indexOf('text/html') > -1);
                 }
 
+                var content;
                 if (isHTML) {
                     // Get the clipboard content.
-                    var content;
                     try {
                         content = event.clipboardData.getData('text/html');
                     } catch (error) {
@@ -179,10 +179,16 @@ EditorClean.prototype = {
                     this.updateOriginal();
                     return false;
                 } else {
-                    // Due to poor cross browser clipboard compatibility, the failure to find html doesn't mean it isn't there.
-                    // Wait for the clipboard event to finish then fallback clean the entire editor.
-                    this.fallbackPasteCleanupDelayed();
-                    return true;
+                    try {
+                        // Plaintext clipboard content can only be retrieved this way.
+                        content = event.clipboardData.getData('text');
+                    } catch (error) {
+                        // Something went wrong. Fallback.
+                        // Due to poor cross browser clipboard compatibility, the failure to find html doesn't mean it isn't there.
+                        // Wait for the clipboard event to finish then fallback clean the entire editor.
+                        this.fallbackPasteCleanupDelayed();
+                        return true;
+                    }
                 }
             } else {
                 // If we reached a here, this probably means the browser has limited (or no) clipboard support.