Dark Launch

Internet Explorer Returns Incorrect JavaScript Object Length

Internet Explorer will incorrectly give an object length off by one if the object contains a trailing comma. In the example below, the alerts return 5 and 6, respectively.
HTML
<!doctype html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title></title>
</head>
<body>
<script type="text/javascript">
alert(
[
'a',
'b',
'c',
'd',
'e'
].length
);
alert(
[
'a',
'b',
'c',
'd',
'e',
].length
);
</script>
</body>
</html>