// preload function
function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

// preload nav roll overs
if(document.images) {
	pre_conf_ovr = newImage("/images/util/n1-conf-events-ovr.gif");
	pre_papers_ovr = newImage("/images/util/n1-publ-papers-ovr.gif");
	pre_tutors_ovr = newImage("/images/util/n1-courses-tutors-ovr.gif");
	pre_res_ovr = newImage("/images/util/n1-ind-res-ovr.gif");
	pre_edu_ovr = newImage("/images/util/n1-students-edu-ovr.gif");
	pre_aiaa_ovr = newImage("/images/util/n1-inside-aiaa-ovr.gif");
	pre_policy_ovr = newImage("/images/util/n1-public-policy-ovr.gif");
	pre_mem_ovr = newImage("/images/util/n1-aiaa-mem-ovr.gif");

}

// function for image rollovers
function changeImg(whichImg,newSrc) {
	if (document.images) {
		document.images[whichImg].src = newSrc;
  	}
	else return;
}

// script to generate random images
var ranNum = (Math.round(Math.random() * 11));  
ranNum = (ranNum == 0) ? 1 : ranNum;  
var choice = ranNum;