Javascript: DOM level 0; Event Listeners (IE Legacy)

gistfile1.js

(function () {

    // HTML items
    // <button>Normal</button>
    // <button>Changed</button>

    // <a href="http://www.google.com">Google</a>
    // <a href="http://www.google.com">Google</a>

    var buttons = document.getElementByTagName('button');
    var links = document.getElementByTagName('a');

    for (var i = 0; len = buttons.length; i < len; i = i + 1) {

        // set class on body element when button is clicked
        // DOM Level 0 events
        buttons[i].onclick = function () {
            var className = this.innerHTML.toLowerCase();
            
            document.body.className = className;
        };

        // listen for 'a' click event
        links[i].addEventListener('click', function (e) {
            var className = this.innerHTML.toLowerCase();

            e.preventDefault();

            document.body.className = className;
        });

        // IE legacy click events
        links[i].attachEvent('onclick', function (e){
            var className = event.srcElement.innerHTML.toLowerCase();

            event.returnValue = false;

            document.body.className = className;
        });
    }

})();