<!DOCTYPE html>
<html>
<head>
<script>
var txt="";
function message()
{
try
adddlert("Welcome guest!");
}
catch(err)
txt="本页有一个错误。\n\n";
txt+="错误描述：" + err.message + "\n\n";
txt+="点击确定继续。\n\n";
alert(txt);
</script>
</head>
<body>
<input type="button" value="查看消息" onclick="message()" />
</body>
</html>