progress.js

$(document).ready(function() {
    //elements
    var progressbar 	= $('#progressbar');
    var statustxt 		= $('#statustxt');
    var submitbutton 	= $("#submit");
    var myform 			= $("#upload");
    var output 			= $("#output");
    var completed 		= '0%';
    $(myform).ajaxForm({
        beforeSend: function() {
            submitbutton.attr('disabled', '');  //dasabilita o o botao submit
            statustxt.empty();

            progressbar.width(completed);
            statustxt.html(completed); //set status text
            statustxt.css('color','#000');
        },
        uploadProgress: function(event, position, total, percentComplete) {
            progressbar.width(percentComplete + '%')

            statustxt.html(percentComplete + '%');
            if(percentComplete>50)
            {
                statustxt.css('color','#000');
            }

        },
        complete: function(response) {

            myform.resetForm();  // reseta o formulario
            submitbutton.removeAttr('disabled'); // habilita o submit


        }
    });
});