function preLoadImgs()
{
	company_overview_on 		= new Image();
	company_overview_on.src 	= "images/nav_company-overview_on.jpg";
	company_overview_off 		= new Image();
	company_overview_off.src 	= "images/nav_company-overview_off.jpg";

	portfolio_on 		= new Image();
	portfolio_on.src 	= "images/nav_project-portfolio_on.jpg";
	portfolio_off 		= new Image();
	portfolio_off.src 	= "images/nav_project-portfolio_off.jpg";

	utilities_on 		= new Image();
	utilities_on.src 	= "images/nav_underground-utilities_on.jpg";
	utilities_off 		= new Image();
	utilities_off.src 	= "images/nav_underground-utilities_off.jpg";

	safety_training_on 		= new Image();
	safety_training_on.src 	= "images/nav_safety-training_on.jpg";
	safety_training_off 		= new Image();
	safety_training_off.src 	= "images/nav_safety-training_off.jpg";

	contact_us_on 		= new Image();
	contact_us_on.src    = "images/nav_contact-us_on.jpg";
	contact_us_off 		= new Image();
	contact_us_off.src   = "images/nav_contact-us_off.jpg";
}


function imgAct(imgName) 
{
	 document[imgName].src = eval(imgName + "_on.src");
}

function imgInact(imgName) 
{
	document[imgName].src = eval(imgName + "_off.src");
}