<!DOCTYPE html>
<html>
<head>
<title> new document </title>
<script >
var oBtn = document.getElementById('btn');
oBtn.onclick = function(){
var isOpen = confirm('是否打开网站？');
if(isOpen){
window.open('http://www.imooc.com','_blank','width:500,height:500');
}
else{
alert('再见')；
}
}
</script>
</head>
<body>
<input id="btn" type="button" value="新窗口打开网站" />
</body>
</html>
if(isOpen==true){}