// declare globals
var buttonOn = new Array();
var buttonOff = new Array();

var i = 0;

var catalog = i++;
var newsletter = i++;
var HCS = i++;
var featured = i++;
var update = i++;
var technical = i++;
var mcLink = i++;
var conferences = i++;
var topics = i++;
var sites = i++;
var services = i++;
var y2k = i++;
var about = i++;
var home = i++;
var trc = i++;


// preload images
buttonOff[catalog] = new Image(160,19);		buttonOn[catalog] = new Image(160,19);
buttonOff[newsletter] = new Image(160,19);	buttonOn[newsletter] = new Image(160,19);
buttonOff[HCS] = new Image(160,19);			buttonOn[HCS] = new Image(160,19);
buttonOff[featured] = new Image(160,19);		buttonOn[featured] = new Image(160,19);
buttonOff[update] = new Image(160,19);		buttonOn[update] = new Image(160,19);
buttonOff[technical] = new Image(160,19);		buttonOn[technical] = new Image(160,19);
buttonOff[mcLink] = new Image(160,19);		buttonOn[mcLink] = new Image(160,19);
buttonOff[conferences] = new Image(160,19);	buttonOn[conferences] = new Image(160,19);
buttonOff[topics] = new Image(160,19);		buttonOn[topics] = new Image(160,19);
buttonOff[sites] = new Image(160,19);		buttonOn[sites] = new Image(160,19);
buttonOff[services] = new Image(160,19);		buttonOn[services] = new Image(160,19);
buttonOff[y2k] = new Image(160,19);			buttonOn[y2k] = new Image(160,19);
buttonOff[about] = new Image(160,19);		buttonOn[about] = new Image(160,19);
buttonOff[home] = new Image(78,19);			buttonOn[home] = new Image(78,19);
buttonOff[trc] = new Image(82,19);			buttonOn[trc] = new Image(82,19);

buttonOff[catalog].src = "../nav_catalog.gif";			buttonOn[catalog].src = "../nav_catalog_on.gif";
buttonOff[newsletter].src = "../nav_newsletters.gif";		buttonOn[newsletter].src = "../nav_newsletters_on.gif";
buttonOff[HCS].src = "../nav_hcs.gif";				buttonOn[HCS].src = "../nav_hcs_on.gif";
buttonOff[featured].src = "../nav_featured.gif";		buttonOn[featured].src = "../nav_featured_on.gif";
buttonOff[update].src = "../nav_update.gif";			buttonOn[update].src = "../nav_update_on.gif";
buttonOff[technical].src = "../nav_technical.gif";		buttonOn[technical].src = "../nav_technical_on.gif";
buttonOff[mcLink].src = "../nav_mclink.gif";			buttonOn[mcLink].src = "../nav_mclink_on.gif";
buttonOff[conferences].src = "../nav_conferences.gif";	buttonOn[conferences].src = "../nav_conferences_on.gif";
buttonOff[topics].src = "../nav_trans_topics.gif";		buttonOn[topics].src = "../nav_trans_topics_on.gif";
buttonOff[sites].src = "../nav_trans_sites.gif";		buttonOn[sites].src = "../nav_trans_sites_on.gif";
buttonOff[services].src = "../nav_services.gif";		buttonOn[services].src = "../nav_services_on.gif";
buttonOff[y2k].src = "../nav_y2k.gif";				buttonOn[y2k].src = "../nav_y2k_on.gif";
buttonOff[about].src = "../nav_about.gif";			buttonOn[about].src = "../nav_about_on.gif";
buttonOff[home].src = "../nav_home.gif";				buttonOn[home].src = "../nav_home_on.gif";
buttonOff[trc].src = "../nav_trc.gif";				buttonOn[trc].src = "../nav_trc_on.gif";



// function for changing images
function change(docNumber, scriptNumber, onOff) {
	if (onOff)
		document.images[docNumber].src = buttonOn[scriptNumber].src;
	else
		document.images[docNumber].src = buttonOff[scriptNumber].src;
}