请问我这段代码哪里错了？求助！！
<!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 open=confirm("是否打开新的网页？");
if(open==ture){
var url=prompt("请输入要打开网页的网址","www.baidu.com");
if(url==ture){
window.open(url,"_blank",'width=400px,height=500px,menubar=no,toolbar=no');
}
else {
alert("再见！")
}
}
else {
alert("再见！")
}
}
</script>
</head>
<body>
<input type="button" name="buttom" value="点击我，打开新的网页" onclick="openwindow()">
</body>
</html>
