ProgressJs is a JavaScript and CSS3 library which helps developers create and manage progress bars for any object on the page. You can design your own template for progress bars or simply customize them.

You can use ProgressJs to show the progress of loading contents (images, videos, etc.) on the page to the users. It can be used on all elements including textboxes, textareas or even the whole body.

It's light-weight, easy to use, customizable, free and open-source.