EDIT
bar
to progress-bar
in v3.1.1HTML
<div class="container">
<div class="progress progress-striped active">
<div class="bar" style="width: 0%;"></div>
</div>
</div>?
CSS
@import url('http://twitter.github.com/bootstrap/assets/css/bootstrap.css');
.container {
margin-top: 30px;
width: 400px;
}?
jQuery used in the fiddle below and on the document.ready
$(document).ready(function(){
var progress = setInterval(function() {
var $bar = $('.bar');
if ($bar.width()>=400) {
clearInterval(progress);
$('.progress').removeClass('active');
} else {
$bar.width($bar.width()+40);
}
$bar.text($bar.width()/4 + "%");
}, 800);
});?
Demo