关于IE7 IE8弹出窗口顶上

代码如下:
1. <script type="text/javascript">
2. function doInput()
3. {
4. var win = window.showModalDialog("http://www.baidu.com?source="+Math.random(),window,"dialogWidth=350px;dialogHeight=400px;center=yes;");
5. }
6. </script>