function mouse_over(obj) {
	obj.src = obj.src.replace(".png","_over.png");
}

function mouse_out(obj) {
	obj.src = obj.src.replace("_over.png",".png");
}

function load_page(pageName) {
	iframe = document.getElementById('iframe_content');
	fileRegExp = new RegExp('[a-zA-Z0-9]+\.html');
	iframe.src = iframe.src.replace(fileRegExp, pageName);
}