if(document.images){
//preload
var btHomeOff = new Image; btHomeOff.src = "img/mainnav-home-off.gif";
var btHomeOver = new Image; btHomeOver.src = "img/mainnav-home-on.gif";
var btProfileOff = new Image; btProfileOff.src = "img/mainnav-profile-off.gif";
var btProfileOver = new Image; btProfileOver.src = "img/mainnav-profile-on.gif";
var btPracticeOff = new Image; btPracticeOff.src = "img/mainnav-practice-off.gif";
var btPracticeOver = new Image; btPracticeOver.src = "img/mainnav-practice-on.gif";
var btLawyersOff = new Image; btLawyersOff.src = "img/mainnav-lawyers-off.gif";
var btLawyersOver = new Image; btLawyersOver.src = "img/mainnav-lawyers-on.gif";
var btCareersOff = new Image; btCareersOff.src = "img/mainnav-careers-off.gif";
var btCareersOver = new Image; btCareersOver.src = "img/mainnav-careers-on.gif";
var btContactOff = new Image; btContactOff.src = "img/mainnav-contact-off.gif";
var btContactOver = new Image; btContactOver.src = "img/mainnav-contact-on.gif";
}

function chgImg(origImg,newImg)
{
	if (document.images){
	document[origImg].src = eval(newImg + ".src")
	}
}