How to make a progress bar

You can do it by controlling the width of a div via css. Something roughly along these lines:

<div id="container" style="width:100%; height:50px; border:1px solid black;">
  <div id="progress-bar" style="width:50%;/*change this width */
       background-image:url(someImage.png);
       height:45px;">
  </div>
</div>

That width value can be sent in from php if you so desire.

If you are using HTML5 its better to make use of <progress> tag which was newly introduced.

<progress value="22" max="100"></progress>

Or create a progress bar of your own.

Example written in sencha

if (!this.popup) {
            this.popup = new Ext.Panel({
            floating: true,
            modal: false,
            // centered:true,
            style:'background:black;opacity:0.6;margin-top:330px;',
            width: '100%',
            height: '20%',
            styleHtmlContent: true,
            html: '<p align="center" style="color:#FFFFFF;font-size:12px">Downloading Data<hr noshade="noshade"size="7" style="color:#FFFFFF"></p>',

            });
}
this.popup.show('pop');

http://jqueryui.com/demos/progressbar/

Check that out, it might be what you need.