function preloadButtons(container) {
	if ( document.getElementById && document.getElementsByTagName ) {
		var imgs = document.getElementById(container).getElementsByTagName("img");
		var img;
		var imgSrc;
		var imgHLSrc;
		var dotPos;
		for (var i = 0; i < imgs.length; i++) {
			img = imgs[i];
			imgSrc = img.src;
			dotPos = imgSrc.lastIndexOf(".");
			if ( dotPos > 0 ) {
				// Assume that img hl sources end in "_hl." and the extension
				imgHLSrc = imgSrc.substring(0,dotPos)+"_hl"+imgSrc.substring(dotPos);
				
				(new Image()).src = imgHLSrc;
	
				eval("img.onmouseout = function() { this.src = '"+imgSrc+"'; }");
				eval("img.onmouseover = function() { this.src = '"+imgHLSrc+"'; }");
			}
		}
	}
}