function hasClass(ele, cls) {
    return ele.className.match(new RegExp('(\\s|^)' + cls + '(\\s|$)'));
}
 
function addClass(ele, cls) {
    if (!hasClass(ele, cls)) {
        ele.className += ' ' + cls;
    }
}
 
function removeClass(ele, cls) {
    if (hasClass(ele, cls)) {
        var reg = new RegExp('(\\s|^)' + cls + '(\\s|$)'),
            newClass = ele.className.replace(reg, ' ');
        ele.className = newClass.replace(/^\s+|\s+$/g, '');
    }
}
//javascript/5204