var addListener = (function() {
    if ( window.addEventListener ) {
        return function(el, type, fn) {
            el.addEventListener(type, fn, false);
        };
    } else if ( window.attachEvent ) {
        return function(el, type, fn) {
            var f = function() {
                fn.call(el, window.event);
            };
            el.attachEvent('on'+type, f);
        };
    } else {
        return function(el, type, fn) {
            element['on'+type] = fn;
        }
    }
})();

addListener(window,"load",init_rollover);

//画像名が_offになっている場合、ロールオーバー
function init_rollover(){
	//img画像
	var imageNodes = document.getElementsByTagName("img");
	var img_len = imageNodes.length
	if(img_len > 0){
		for(var i = 0; i < img_len; i++){
			var img = imageNodes[i];
			if(img.src && img.src.lastIndexOf("_off.") >= 0){
				addListener(img,"mouseover",btnOver);
				addListener(img,"mouseout",btnOut);
			}
		}
	}
	// input画像
	var inputNodes = document.getElementsByTagName("input");
	var input_len = inputNodes.length
	if(input_len > 0){
		for(var i = 0; i < input_len; i++){
			var input = inputNodes[i];
			if(input.type == "image" && input.src && input.src.lastIndexOf("_off.") >= 0){
				addListener(input,"mouseover",btnOver);
				addListener(input,"mouseout",btnOut);
			}
		}
	}
	function btnOver(e){
		var obj = e.target ? e.target : e.srcElement;
		obj.src = obj.src.split("_off.").join("_on.");
	}
	function btnOut(e){
		var obj = e.target ? e.target : e.srcElement;
		obj.src = obj.src.split("_on.").join("_off.");
	}
}