Bootstrap 3 Skeleton

This is a simple Bootstrap skeleton. You can fork it to get a ready to use Bootstrap fiddle.

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.1.0/bootstrap.min.js"></script>
<body>
        <div id="progressbar" class="progressbar" onclick="this.style.width='90%';"></div>
    </body>

CSS

@import url('http://getbootstrap.com/dist/css/bootstrap.css');
.progressbar
        {
            position: relative;
            width: 100px;
            height: 10px;
            background-color: red;
        }

        .progressbar:after
        {
            content: "";
            position: absolute;
            width: 25%;
            height: 100%;
            background-color: blue;
        }

JavaScript

//create new style element
var style = document.createElement("style");

//append the style
document.head.appendChild(style);

//take the stylesheet object
sheet = style.sheet

//add the rule to your stylesheet
sheet.insertRule('.progressbar::after { width: 50% }', 0);