var mRovel = new Object();

mRovel = function() {
	var element = document.getElementsByTagName('img');
	for (var i = 0; i < element.length; i++) {
		if (element[i].className == 'mRovel[img]') {
			element[i].onmouseover = mRovel.over = function() {
				var srcObraz = this.src;
				var srcObrazLength = srcObraz.length;
				var obrazPlik = srcObraz.substring(srcObrazLength - 4, srcObrazLength);
				var obraz = srcObraz.substring(0, srcObrazLength - 7) + 'on' + obrazPlik;
				this.src = obraz;
			};
			element[i].onmouseout = mRovel.out = function() {
				var srcObraz = this.src;
				var srcObrazLength = srcObraz.length;
				var obrazPlik = srcObraz.substring(srcObrazLength - 4, srcObrazLength);
				var obraz = srcObraz.substring(0, srcObrazLength - 6) + 'off' + obrazPlik;
				this.src = obraz;
			};
		}
	}	
};

window.onload = mRovel;