[monolithed]

Vulkan, все проще, ваш вариант не кроссбраузерный:

<script type="text/javascript">
window.onload = function() {
    var getElementsByClassName = function(getClass){
        if(document.querySelectorAll) {
            return document.querySelectorAll("." + getClass);
        }
        else if(document.getElementsByClassName) {
            return document.getElementsByClassName(getClass);
        }
        else {
            var list = document.getElementsByTagName('*'), i = list.length,
            classArray = getClass.split(/\s+/), result = [];
            while(i--) {
                if(list[i].className.search('\\b' + classArray + '\\b') != -1) {
                    result.push(list[i]);
                }
            }
            return result;
        }
    };
    
    var handler = ['mouseover','mouseout'], i = handler.length;
    
    while(i--) {
        getElementsByClassName('class')[0]['on'+handler[i]] = function () {
        this.style.color = this.style.color == '' ? '#ff0000' : '';
        }
    }
};
</script>
<a href="#" class="class">ссылка</a>