JSFiddler 的系统似乎也认为这没问题,但也不会显示警报。http://jsfiddle.net/dmafackler/zEEpB/3/
<!doctype html>
<html>
<head>
<title>foobar</title>
<script type="text/javascript" src="jquery.js" />
<script type="text/javascript">
$(document).ready(function() { alert("Is anybody home?"); });
</script>
</head>
<body>
<p>Copasetic.</p>
</body>
</html>