typeout.js

// My quick hack to making a typing animation on screen, without silly JQuery...

// typeOut takes the: 
// element: DOM element to manipulate
// string: string to type out
// delay: time between keystrokes
function typeOut (element, string, delay) {
    for(var i = 0; i < string.length; i++){
        (function(){
            var tempI = i;
            setTimeout(function(){
                document.getElementById(element).innerHTML = string.substr(0, tempI+1);
            }, delay + delay * tempI);
        })();
    }
}

function ready () {
    typeOut('intro', 'Hello World...', 100);
}

document.onload = ready();

Unit tests?