如何用javascript访问本地文件

<script language="javascript">
var s;
s="";
function ShowFolderFileList(i,folderspec)
{
var fso,f,fc,name;
var url,str,file,filename;
var i;
fso = new ActiveXObject("Scripting.FileSystemObject");
f = fso.GetFolder(folderspec);
s += i++ + "\t" + f.Name + "\t\n";
fc = new Enumerator( f.files );
for (; !fc.atEnd(); fc.moveNext( ) )
{
filename = fso.GetFileName( fc.item( ) );
if (filename.indexOf(".url")>=0)
{
filename = filename.substring( 0 , filename.length-4 );
file = fso.GetFile( fc.item( ) );
ts = file.OpenAsTextStream( 1 , 0 );
str=ts.ReadLine();
while( str.indexOf( "URL=" ) < 0 && !ts.AtEndOfStream )
{
str = ts.ReadLine( );
}
ts.Close( );
s += i + "\t" + filename + "\t" + str.substr( str.indexOf( "URL=") + 4 ) + "