var isMoz;
window.addEventListener ? isMoz = true : isMoz = false;
var eMoz = 'target';
var eIE = 'srcElement';
var objImgOver = new Image();
objImgOver.src = '/images/how-to/javascript/button-active.gif';
var objImgOut = new Image();
objImgOut.src = '/images/how-to/javascript/button-inactive.gif';

function initMouseOver() {
	var objImage = document.getElementById('button');
	if (isMoz) {
		objImage.addEventListener('mouseover', imgOver, false);
		objImage.addEventListener('mouseout', imgOut, false);
	}
	else {
		objImage.attachEvent('onmouseover', imgOver);
		objImage.attachEvent('onmouseout', imgOut);
	}
}
function imgOver(e) {
	e[eMoz] ? e[eMoz].src = objImgOver.src : e[eIE].src = objImgOver.src;
}
function imgOut(e) {
	e[eMoz] ? e[eMoz].src = objImgOut.src : e[eIE].src = objImgOut.src;
}