<html>
<head>
<script>
function test()
{
    document.getElementById('tf').focus();
    document.execCommand("InsertText", false, 'Test Failed');
}
</script>
</head>
<body onload="test()">
This tests that text can not be inserted into a disabled text field.<br><input id="tf" style="-khtml-appearance: textfield;" disabled value="Test Passed"></input>
</body>
</html>