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JS to determine the size of the upload file

Source: Internet
Author: User
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Below provide three pages of special effects to judge upload file size Oh, these three methods are now limited file upload size is a better way, you can upload files when the user limit the size of the upload file to judge processing
<!doctype HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd" >
<html xmlns= "http://www.w3.org/1999/xhtml" >
<head>
<meta http-equiv= "Content-type" content= "HTML; charset=gb2312 "/>
<title>js to judge upload file size </title>
</head>

<body>
Method One

<input type= "File" Name= "File1" onchange= "Showsize (this.value)" >
<script language= "Web Effects" >
<!--
function showsize (Files)
{
var fso,f;
Fso=new ActiveXObject ("Scripting.FileSystemObject");
F=fso.getfile (files);
if (f.size>1024*4) {
Alert (f.size+ "bytes");
}
}
-->
</script> method Two JS to determine the size of the upload file

<script type= "text/javascript"
    function Chksize (strfilename) {
         try
        {
          var maxsize = 100;    //definition of allowable file size, KB, please modify as required!
         var objstream = new ActiveXObject ("ADODB.stream");
         objStream.Type = 1;
         objStream.Open ();
         objStream.LoadFromFile (strFileName);
         if (Math.Round (objstream.size/1024) >maxsize)
              {alert ("Sorry!) The file you selected is "+math.round (objstream.size/1024,2) +" KB n exceeds the limit of the program "+maxsize+" KB! ");
             Document.form1.reset ();
             return false;
        }
         Else
             alert ("Can upload");
       }catch (e)
        {
            alert ("Not supported");
       }
   }
</script><
Form name= "Form1" action= "method=" POST "
<input type=" file "Name=" Upfile " Onchange= "Chksize (this.value)"/>//method three

<script>   
 
function getfilesize (filename) {   
     
if (document.all) {   
Window.oldonerror = window.onerror;        
Window.onerror = function (err) {   
if Err.indexof (' Utomation ')!=-1) {   
Alert (' No permissions to access files ');            
Return true;         
}         
else    
Return false;        
};   
    var fso = new ActiveXObject (' Scripting.FileSystemObject ' ;   
    var file = fso.getfile (filename);        
Window.onerror = window.oldonerror;   
    return file.size; }}   
</script>   
</head>    
  
<form name= "FormName" ><input type= "file" name= "filename" ><br>    
<input type= button "value=" View file byte size "onclick=" alert (GetFileSize (This.form.filename.value)) ><br>   
</form>
JavaScript to determine the size of the client file, JS to determine the size of the upload file, js get file length
</body
</html>
 

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