JavaScript下利用fso判断文件是否存在的代码

function ReportFileStatus(filespec) 
{ 
var fso, s = filespec; 
fso = new ActiveXObject("Scripting.FileSystemObject"); 
if (fso.FileExists(filespec)) 
s += " exists."; 
else 
s += " doesn't exist."; 
return(s); 
}

function check() 
{ 
var fso; 
fso = new ActiveXObject("Scripting.FileSystemObject"); 
if( fso.FileExists("c:\\testfile.txt")) 
{ 
alert("Exists!"); 
} 
else 
{ 
alert("not Exists!"); 
} 
}