请教程序某一处的意思...
<head><script type="text/javascript">
var txt=""
function message()
{
try
{
adddlert("Welcome guest!")
}
catch(err)
{
txt="There was an error on this page.nn"
txt+="Error description: " + err.description + "nn"
txt+="Click OK to continue.nn"
alert(txt)
}
}
</script>
</head>
<body>
<input type="button" value="View message" onclick="message()" />
</body>
catch(err)
{
txt="There was an error on this page.nn"
txt+="Error description: " + err.description + "nn"
txt+="Click OK to continue.nn"
alert(txt)
这里面为什么这么多nn呢，是什么意思啊？page.nn和continue.nn又分别是什么意思呢？
