<script language="javascript">function FileExist(){　　var sfso=new ActiveXObject("Scripting.FileSystemObject");　　var fPath="[The path of the file]";　　if(sfso.FileExists(fPath))　　{     　　alert("Exist");　　}　　else　　{　　　　alert("Doesn't exist");   　}}</script>

<script language="javascript">function FileExist(){　　var xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");　　xmlhttp.open("GET",FileURL,false);    xmlhttp.send();    if(xmlhttp.readyState==4)　　{      　　if(xmlhttp.status==200) alert("Exist");      　 else if(xmlhttp.status==404) alert("Doesn't exist");      　else alert("Don't know");    　} }</script>