Simple debug hud

hud.js

var hud = function(msg, length) {
    var length = length || 2;
    window.hudBuffer = window.hudBuffer || [];

    window.hudBuffer.push(msg);
    if(window.hudBuffer.length > length) {
        window.hudBuffer.shift();
    }

    hudString = "";
    for(var i in window.hudBuffer) {
        hudString = new String(new Date().getTime()).substr(9)+": "+window.hudBuffer[i]+"<br />"+hudString;
    }
    var hudDom = document.getElementById('hud');
    if(hudDom == null) {
        var hudDom = document.createElement('div');
        hudDom.setAttribute('id','hud');
        hudDom.setAttribute('style','position:fixed;top:10;left:10px;padding:10px;color:#fff;background:#000;z-index:10000;');
        document.body.appendChild(hudDom);
    }
    hudDom.innerHTML = hudString;
};