if (document.getElementsByTagName) {
	toggle = function(a) {
		var img = a.getElementsByTagName('img')[0];
		var src = img['src'];
		if (src.indexOf('_hi.') > -1) 
			img["src"] = src.replace("_hi.", "."); 
		else 
			img["src"] = src.replace(".gif", "_hi.gif"); 
	};
}
else {	
	toggle = function() { return; };
}