Customize input file for twitter bootstrap

gistfile1.html

<div style="position:relative;">
                <a class='btn' href='javascript:;'>
                    Choose File...
                    <input type="file" style='position:absolute;z-index:2;top:0;left:0;filter: alpha(opacity=0);-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=0)";opacity:0;background-color:transparent;color:transparent;' name="file_source" size="40"  onchange='$("#upload-file-info").html($(this).val());'>
                </a>
                &nbsp;
                <span class='label label-info' id="upload-file-info"></span>
            </div>