<html>
<head>
<title>判断一个对象是否存在</title>
</head>
<body>
<script language="javascript">
<!--
function person(){}
Jim = new person();
if(window.Jim){
document.write("Jim对象存在");
}else{
document.write("Jim对象不存在");
}
//-->
</script>
</body>
</html>