if (document.images)
{
	btn1on=new Image();
	btn1on.src="images/btn_home_on.gif";
	btn2on=new Image();
	btn2on.src="images/btn_about_on.gif";
	btn3on=new Image();
	btn3on.src="images/btn_products_on.gif";
	btn4on=new Image();
	btn4on.src="images/btn_contact_on.gif";

	btn1off=new Image();
	btn1off.src="images/btn_home_off.gif";
	btn2off=new Image();
	btn2off.src="images/btn_about_off.gif";
	btn3off=new Image();
	btn3off.src="images/btn_products_off.gif";
	btn4off=new Image();
	btn4off.src="images/btn_contact_off.gif";
}

function btnToggle(imgName,state)
{
	if (document.images)
	{
		document[imgName].src = eval(imgName + state + ".src");
	}
}