Plain JavaScript toggleClass function. Relies on hasClass function defined in separate Gist

js-toggle-class.js

function toggleClass(element, className) {
    var newClass = ' ' + element.className.replace( /[\t\r\n]/g, ' ' ) + ' ';
    if(hasClass(element, className)) {
        while(newClass.indexOf(' ' + className + ' ') >= 0) {
            newClass = newClass.replace(' ' + className + ' ' , ' ');
        }
        element.className = newClass.replace(/^\s+|\s+$/g, '');
    } else {
        element.className += ' ' + className;
    }
}