isIE = (navigator.appName == 'Microsoft Internet Explorer');
isV5 = (parseFloat(navigator.appVersion)>=5.0);

if (document.images) {
	rollOvers = 1;
} else {
	rollOvers = 0;
}

loaded = 0;

function loadImg() {
	if (rollOvers) {
		bt1On = new Image();
		bt1On.src = "../company/img/bt1_over.gif";
		bt2On = new Image();
		bt2On.src = "../company/img/bt2_over.gif";
		bt3On = new Image();
		bt3On.src = "../company/img/bt3_over.gif";
		bt4On = new Image();
		bt4On.src = "../company/img/bt4_over.gif";
		

		bt1Off = new Image();
		bt1Off.src = "../company/img/bt1.gif";
		bt2Off = new Image();
		bt2Off.src = "../company/img/bt2.gif";
		bt3Off = new Image();
		bt3Off.src = "../company/img/bt3.gif";
		bt4Off = new Image();
		bt4Off.src = "../company/img/bt4.gif";
		
		loaded = 1;
	}
}

function switchOn(imgName) {
	if (loaded == 1) {
		imgOn = eval(imgName+"On.src");
		document[imgName].src = imgOn;
	}
}

function switchOff(imgName) {
	if (loaded == 1) {
		imgOff = eval(imgName+"Off.src");
		document[imgName].src = imgOff;
	}
}

if (isIE || isV5) {
	loadImg();
}