How can if find the size of a file prior to upload, with the help of jquery?

I want to check the file size before uploading it, so that i can restrict the users before uploading开发者_高级运维. I want it use the jquery, but please suggest some thing else, if it is not possible in that way. I am using PHP at backend.

You can't check file size with Javascript. This is a security restriction. The only way you can do it is only using server-side scripting.

You can't with Javascript, but you can using a Flash based uploader such as SWFUpload.

You cannot. It's a security restriction in Javascript/HTML. Best what you can do is to use a real programming language for which you can write client-side applications which you on its turn can embed in a web page, such as a (signed!) Java Applet or Java Web Start (aka JNLP).

This is not possible via JavaScript. You could try to use any kind of browser plugin to perform these test. FlashPlayer offers these kind of possibilities.