do not use innerHTML

gistfile1.js

//when you do this:
elem.innerHTML = 'I want to set elem\'s text!';

//you're calling the browser's html parser. why so surprised? innerHTML takes an html string and turns it into DOM elements.
//you can't do that without calling an html parser.
//after the browser is done parsing your (invalid) html, it sees that it only contains text and _assumes_ you just want text and puts it into
//a text node.
//now what? it empties the element out of everything and appends the new text node. it then re-parses, re-flows and re-paints your entire page
// (since your innerHTML call can do many other things, and affect everything else in the page)

//this. is. wrong. not sparta at all. to create a text node, you're re-making your page. why don't you use the _correct_ DOM methods?

//textContent is standard. however, it doesn't work in IE
elem.textContent = 'Look mom, I\'m text!';

//innerText is an IE beast, but doesn't work in FF
elem.innerText = 'Look mom, I\'m text!';

//both of the above empty the element before adding text. I recommend the following:

var textNode = document.createTextNode( 'Look mom! I\'m a text node!' );
elem.appendChild( textNode );

//standard, works in everything, and does what you'd expect it to do. if you want to remove everything from elem, do it explicitly.