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

The following seems to work reliably in Chrome and Firefox (Ubuntu 10.10), I'm unable to check on other platforms at the moment:

jQuery

$(document).ready(
    function(){
        $('input:file').change(
            function(){
                if ($(this).val()) {
                    $('input:submit').attr('disabled',false);
                    // or, as has been pointed out elsewhere:
                    // $('input:submit').removeAttr('disabled'); 
                } 
            }
            );
    });

html

Demo at JS Fiddle.