javascript innerHTML adding instead of replacing

Answer 1

If you are appending, you can just change your = to a +=

document.getElementById("whatEverId").innerHTML += 'hello two';

If prefixing

document.getElementById("whatEverId").innerHTML = 'hello two' + document.getElementById("whatEverId").innerHTML;

Although I would highly recommend using jQuery or MooTools javascript libraries/frameworks to do this sort of thing. If you're adding tags not just text nodes, then you should use the DOM createElement or one of the aforementioned libraries/frameworks.