I have a page with several bootstrap progress bars. Setting their values initially works fine. Though I would like the progress bars to animate/transition to their specific states when a user opens the page.

This JS works fine, when you click on one of the bars. I would need something like that on an "onload" event of the bar. But the "onload" event is not available for s

//animate progress bars
$('.progress .bar').on("click", function(event) {
  var me = $(this);
  perc = me.attr("data-percentage");
  me.css('width', perc+'%');
});

How can I achieve this behavior on page load for all progress bars on a page?

• javascript
• jquery
• twitter-bootstrap

While Tats_innit's answer has a nice touch to it, I had to do it a bit differently since I have more than one progress bar on the page.

here's my solution:

JSfiddle: http://jsfiddle.net/vacNJ/

HTML (example):

<div class="progress progress-success">
<div class="bar" style="float: left; width: 0%; " data-percentage="60"></div>
</div>

<div class="progress progress-success">
<div class="bar" style="float: left; width: 0%; " data-percentage="50"></div>
</div>

<div class="progress progress-success">
<div class="bar" style="float: left; width: 0%; " data-percentage="40"></div>
</div>

​

JavaScript:

setTimeout(function(){

    $('.progress .bar').each(function() {
        var me = $(this);
        var perc = me.attr("data-percentage");

        var current_perc = 0;

        var progress = setInterval(function() {
            if (current_perc>=perc) {
                clearInterval(progress);
            } else {
                current_perc +=1;
                me.css('width', (current_perc)+'%');
            }

            me.text((current_perc)+'%');

        }, 50);

    });

},300);

@Tats_innit: Using setInterval() to dynamically recalc the progress is a nice solution, thx mate! ;)

EDIT:

A friend of mine wrote a nice jquery plugin for custom twitter bootstrap progress bars. Here's a demo: http://minddust.github.com/bootstrap-progressbar/

Here's the Github repo: https://github.com/minddust/bootstrap-progressbar

EDIT

• Class name changed from bar to progress-bar in v3.1.1

HTML

<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

JSFiddle

Updated JSFiddle

Bootstrap uses CSS3 transitions so progress bars are automatically animated when you set the width of .bar trough javascript / jQuery.

http://jsfiddle.net/3j5Je/ ..see?

In contribution to ellabeauty's answer. you can also use this dynamic percentage values

$('.bar').css('width',  function(){ return ($(this).attr('data-percentage')+'%')});

And probably add custom easing to your css

.bar {
 -webkit-transition: width 2.50s ease !important;
 -moz-transition: width 2.50s ease !important;
   -o-transition: width 2.50s ease !important;
      transition: width 2.50s ease !important;
 }

Here's a cross-browser CSS-only solution. Hope it helps!

DEMO

.progress .progress-bar {
    -moz-animation-name: animateBar;
    -moz-animation-iteration-count: 1;
    -moz-animation-timing-function: ease-in;
    -moz-animation-duration: .4s;

    -webkit-animation-name: animateBar;
    -webkit-animation-iteration-count: 1;
    -webkit-animation-timing-function: ease-in;
    -webkit-animation-duration: .4s;

    animation-name: animateBar;
    animation-iteration-count: 1;
    animation-timing-function: ease-in;
    animation-duration: .4s;
}

@-moz-keyframes animateBar {
    0% {-moz-transform: translateX(-100%);}
    100% {-moz-transform: translateX(0);}
}
@-webkit-keyframes animateBar {
    0% {-webkit-transform: translateX(-100%);}
    100% {-webkit-transform: translateX(0);}
}
@keyframes animateBar {
    0% {transform: translateX(-100%);}
    100% {transform: translateX(0);}
}

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>

<div class="container">
  
  <h3>Progress bar animation on load</h3>
  
  <div class="progress">
    <div class="progress-bar progress-bar-success" style="width: 75%;"></div>
  </div>
</div>