(function(onLoad) {  
try {  
window.addEventListener('load', onLoad, false);  
} catch (e) {  
window.attachEvent('onload', onLoad);  
}  
})(function() {  
var tags = ["img","input"];  
for( var i=0, len=tags.length; i<len; i++ ) {  
var over = function() { this.src = this.src.replace('_off.', '_on.'); };  
var out  = function() { this.src = this.src.replace('_on.', '_off.'); };  
var el = document.getElementsByTagName(tags[i]);  
for (var j=0, len2=el.length; j<len2; j++) {  
var attr = el[j].getAttribute('src');  
if (!el[j].src.match(/_off\./)&&attr) continue;  
el[j].onmouseover = over;  
el[j].onmouseout  = out;  
}  
}  
});