<!DOCTYPE html>
<html>
<head>
<title> new document </title>
<meta http-equiv="Content-Type" content="text/html; charset=gbk"/>
<script type="text/javascript">
function openWindow(){
var openmessage=confirm("是否打开窗口？")
if(openmessage==true)
{
var srdwz;
srdwz=prompt("请输入您将要访问的地址：","http：//www.imooc.com/");
window.open(srdwz,"_blank","width=600,height=400,top=100,menubar=no,toolbar=no,status=no,scrollbars=no")
}
}
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>
刚试了，你的http后面的冒号是中文状态下的，换成英文的就可以了