var fso,s=filespec; // filespec="C:/path/myfile.txt"fso=new ActiveXObject("Scripting.FileSystemObject");if(fso.FileExists(filespec))s+=" exists.";else // www.49028c.coms+=" doesn't exist.";alert(s);

var xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");xmlhttp.open("GET",yourFileURL,false);xmlhttp.send();if(xmlhttp.readyState==4){if(xmlhttp.status==200)s+=" exists."; //url存在else if(xmlhttp.status==404)s+=" doesn't exist."; //url不存在else s+="";//其他狀態} // www.yuju100.comalert(s);