make preview example work in IE 7/8

fbuchinger · marijnh · commit 37b7eafec25a · 2011-09-26T10:56:51.000+02:00
diff --git a/demo/preview.html b/demo/preview.html
@@ -36,6 +36,7 @@ <h1>CodeMirror 2: HTML5 preview</h1>
     <meta charset=utf-8>
   </head>
   <body>
+   <p>Canvas pane goes here:</p>
     <canvas id=tutorial width=250 height=250></canvas>
     <script>
       var canvas = document.getElementById('tutorial');
@@ -64,7 +65,8 @@ <h1>CodeMirror 2: HTML5 preview</h1>
       });
       
       function updatePreview() {
-        var preview = document.getElementById('preview').contentDocument;
+        var previewFrame = document.getElementById('preview');
+        var preview =  previewFrame.contentDocument ||  previewFrame.contentWindow.document;
         preview.open();
         preview.write(editor.getValue());
         preview.close();
