JavaScript file upload size validation

Question

Is there any way to check file size before uploading it using JavaScript?

Answer 1

If you're using jQuery Validation, you could write something like this:

$.validator.addMethod(
    "maxfilesize",
    function (value, element) {
        if (this.optional(element) || ! element.files || ! element.files[0]) {
            return true;
        } else {
            return element.files[0].size <= 1024 * 1024 * 2;
        }
    },
    'The file size can not exceed 2MB.'
);