var Log = {
    elem: false,
    write: function(text){
        if (!this.elem) 
            this.elem = document.getElementById('log');
        this.elem.innerHTML = text;
        this.elem.style.left = (500 - this.elem.offsetWidth / 2) + 'px';
    }
};

function addEvent(obj, type, fn) {
    if (obj.addEventListener) obj.addEventListener(type, fn, false);
    else obj.attachEvent('on' + type, fn);
};