Progress bars have always been a needed element in web applications. Every time a user sends requests to the server, it is quite usual that some sort of immediate response is needed, just to make the user aware that something's really happening and that the whole application is not just frozen. In the past, we used JavaScript and CSS to show some sort of progress bar. We usually used animated gifs like
With HTML5, a new element has been introduced. It is progress and it will give us a new way to show the user that something's really going on after that button has been pressed.
"The HTML progress (<progress>) element is used to view the completion progress of a task. While the specifics of how it's displayed is left up to the browser developer, it's typically displayed as a progress bar." (quote from Mozilla Developer Network).