JS Get upload file size

About JS get upload file size processing principle is to use JS to read the current picture, and then create a new image and then the size of the picture read out, and then determine the current file picture size is not a specified size on OK.

<script language= "Web Effects" >
function showsize (Files)
{
var fso,f;
Fso=new ActiveXObject ("Scripting.FileSystemObject");
F=fso.getfile (files);
var filesize = f.size;
if ((filesize/1024) < 1024) {
Alert (filesize/1024+ "K");
}else if ((filesize/1024) > 1024) && ((filesize/(1024*1024)) < 1024)) {
Alert (filesize/(1024*1024) + "M");
}else{
Alert (filesize/(1024*1024*1024) + "G")
}
}
</script>

Method Two
: <input type= "Text" size= "4" value= "" Name= "Filesizelimit" id= "Filesizelimit"/> k
<input type = "File" name= "File1" id= "file1" size= "" Onchange= "Changesrc" (This)/>
<img src= "About:blank" Filechecker "alt=" test "  height="/>
   
<script type= "Text/javascript"
var ofilechecker = document.getElementById ("Filechecker");
   
Function changesrc (filepicker)
{
    ofilechecker.src = Filepicker.value;
}
   
Ofilechecker.onreadystatechange = function ()
{
    if ( Ofilechecker.readystate = = "complete")
    {
        Checksize ();
   }
}
   
function checksize ()
{
    var limit  = document.getElementById ("Filesizelimit"). Value * 1024;
   
    if (ofIlechecker.filesize > Limit)
    {
        alert ("Too SCM ");
   }
    Else
    {
        alert ("OK");
   }
}
</script>

Method Three JS get upload file size
<script type= "Text/javascript" ><!--
function getfilesize1 (filename) {
var size = null;
var file = null;
if (filename) {
var fso = new ActiveXObject ("Scripting.FileSystemObject");
try{
File=fso.getfile (filename);
Size=file.size;
}
catch (e) {
Return ("Get file error.")
}
}
return (size);
}
-->
</script>

<div>
<input id= "upfile" type= "file" value= "Upload"/>
<button value= "Get Size" onclick= "var msg=getfilesize (document.getElementById (' Upfile '). value); alert (msg);"/ >
</div>