Testing file size before uploading it

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Abstract

there is no way to know file size before  uploading it to your server. http://www.yahoomail.com/ uploads file then check its size if its size exceed 10 MB,  yahoo server revokes it in this way you consuming server's memory and bandwidth.that's a bad deal.

Solution

you have to write some java script code:

<P>function GetSize(file){</P><P>var fso=new ActiveXObject("Scripting.FileSystemObject");</P><P>var f=fso.getFile(file);</P><P>return fso.getFile(file).size;</P><P>}</P>

this function takes file name and returns file size. it uses windows embed ActiveX to get file size.

then you write another function to do calculations:

function checkFileSize(ctrl){



//check if file size is > 10 MB

if(GetSize(ctrl.value)>10485760)//10 MB=10485760 B

{

alert('Sorry file size > 10MB');

ctrl.form.reset();//file grater than 10MB then reset form

}
}

simply it takes Fileupload control reference and call  GetSize function and compare its result to 10485760(10 MB=10485760 B) if the file size exceed 10 MB,it reset form else do nothing and submit form to server.to use this function  put an html button and add this attribute to it onclick="checkFileSize(this.form.File1);".