How can I get a file's upload size using simple Javascript?

Question

I have upload file functionality on one of the page. I check for the extension of the file using JavaScript. Now i want to restrict the user from uploading file greater than

Answer 1

not possible. would be a major security concern to allow client side scripts to run that can read file info from and end users hard drive.

Answer 2

Most of these answers are way out-of-date. It is currently possible to determine file size client-side in any browser that supports the File API. This includes, pretty much, all browsers other than IE9 and older.