disable submit button until file selected for upload

Question

I have a form for uploading images. I\'d like to disable the submit button, until user selects an image to upload. I\'d like to do it with jQuery. Currently I have a JavaScr

Answer 1

If you're a fan of ternary expressions:

$(document).ready(function(){
    var $submit = $('#submit_document');
    var $file = $('#file_path');

    $file.change(
        function(){
            $submit.attr('disabled',($(this).val() ? false : true));
        }
    );
});