/*
Pre-load the primary navigation images
*/
var navA0 = new Image(); navA0.src = "_gui/images/nav-programs-0.gif";
var navA1 = new Image(); navA1.src = "_gui/images/nav-programs-1.gif";
var navB0 = new Image(); navB0.src = "_gui/images/nav-parks-0.gif";
var navB1 = new Image(); navB1.src = "_gui/images/nav-parks-1.gif";
var navC0 = new Image(); navC0.src = "_gui/images/nav-planning-0.gif";
var navC1 = new Image(); navC1.src = "_gui/images/nav-planning-1.gif";
var navD0 = new Image(); navD0.src = "_gui/images/nav-publications-0.gif";
var navD1 = new Image(); navD1.src = "_gui/images/nav-publications-1.gif";
var navE0 = new Image(); navE0.src = "_gui/images/nav-contact-0.gif";
var navE1 = new Image(); navE1.src = "_gui/images/nav-contact-1.gif";
var navF0 = new Image(); navF0.src = "_gui/images/nav-sitemap-0.gif";
var navF1 = new Image(); navF1.src = "_gui/images/nav-sitemap-1.gif";

function roll(img_name, img_src) {
	document[img_name].src = eval(img_src + ".src");
}