function auto_bg(tag_name) {
	if (window.attachEvent) {
		window.attachEvent("onload", function() {
			var el = document.getElementsByTagName(tag_name);
			set_auto_bg(el);
		});
	}
}

function set_auto_bg (el) {
	for (var i=0; i<el.length; i++) {
		el[i].onfocus=function() {
			this.className+=" focused";
		}
		el[i].onblur=function() {
			this.className=this.className.replace(new RegExp(" focused"), "");
		}
	}
}

auto_bg("INPUT");
auto_bg("TEXTAREA");