From http://blog.stevenlevithan.com/archives/faster-than-innerhtml using innerHTML and dom methods to replace elements

replaceHtml.js

	function replaceHtml(el, html) {
		var oldEl = typeof el === "string" ? document.getElementById(el) : el;
		/* @cc_on // Pure innerHTML is slightly faster in IE
			oldEl.innerHTML = html;
			return oldEl;
		@*/
		var newEl = oldEl.cloneNode(false);
		newEl.innerHTML = html;
		oldEl.parentNode.replaceChild(newEl, oldEl);
		// Since we just removed the old element from the DOM, return a reference
		//	to the new element, which can be used to restore variable references.
		return newEl;
	};
	// Example, replace #foo element with 2nd arg.
	//replaceHtml('foo','<div id="bar">Bar</div>');