if (document.images) {
	// ======================= preload rollover main navigation button images
	var nav_home_over = new Image (); nav_home_over.src = "/images/nav_home_over.gif";
	var nav_campaign_over = new Image (); nav_campaign_over.src = "/images/nav_campaign_over.gif";
	var nav_program_over = new Image (); nav_program_over.src = "/images/nav_program_over.gif";
	var nav_event_over = new Image (); nav_event_over.src = "/images/nav_event_over.gif";
	var nav_teacher_over = new Image (); nav_home_over.src = "/images/nav_teacher_over.gif";
	var nav_trial_over = new Image (); nav_home_over.src = "/images/nav_trial_over.gif";
	// ======================= preload rollover EI navigation button images
	var nav_ei_overview_over = new Image (); nav_ei_overview_over.src = "/images/nav_ei_overview_over.gif";
	var nav_ei_program_over = new Image (); nav_ei_program_over.src = "/images/nav_ei_program_over.gif";
	var nav_ei_faq_over = new Image (); nav_ei_faq_over.src = "/images/nav_ei_faq_over.gif";
	var nav_ei_campaign = new Image (); nav_ei_campaign.src = "/images/nav_ei_campaign.gif";
	// ======================= preload rollover some common images

	// ======================= set nav images to off image as default
	var nav_campaign = '<img src="images/nav_campaign.gif" name="nav_camp" width="100" height="28" border="0">';
	var nav_program = '<img src="images/nav_program.gif" name="nav_program" width="100" height="28" border="0">';
	var nav_event = '<img src="images/nav_event.gif" name="nav_event" width="100" height="28" border="0">';
	var nav_teacher = '<img src="images/nav_teacher.gif" name="nav_teacher" width="100" height="28" border="0">';
	var nav_trial = '<img src="images/nav_trial.gif" name="nav_trial" width="100" height="28" border="0">';
		var nav_ei_overview = '<img src="images/nav_ei_overview.gif" name="nav_ei_overview" width="100" height="28" border="0">';
		var nav_ei_program = '<img src="images/nav_ei_program.gif" name="nav_ei_program" width="100" height="28" border="0">';
		var nav_ei_faq = '<img src="images/nav_ei_faq.gif" name="nav_ei_faq" width="100" height="28" border="0">';
		var nav_ei_campaign = '<img src="images/nav_ei_campaign.gif" name="nav_ei_campaign" width="100" height="28" border="0">';


	// ======================= preload rollover images for each page
	if (whichCategory == "home") {
		var promo1_02_over = new Image (); promo1_02_over.src = "/images/promo1_02_over.gif";
		var promo2_02_over = new Image (); promo2_02_over.src = "/images/promo2_02_over.gif";
		var promo3_02_over = new Image (); promo3_02_over.src = "/images/promo3_02_over.gif";
		var bt_pg_02_over = new Image (); bt_pg_02_over.src = "/images/images/bt_pg_02_over.gif";
	}
	if (whichCategory == "program") {
		// set nav images to ON image
		var nav_program = '<img src="images/nav_program_on.gif" name="nav_program" width="100" height="28" border="0">';
		// chart images
		var p_prog_overview_chart_03_over = new Image (); p_prog_overview_chart_03_over.src = "/images/p_prog_overview_chart_03_over.gif";	// EI
		var p_prog_overview_chart_07_over = new Image (); p_prog_overview_chart_07_over.src = "/images/p_prog_overview_chart_07_over.gif";	// PS
		var p_prog_overview_chart_16_over = new Image (); p_prog_overview_chart_16_over.src = "/images/p_prog_overview_chart_16_over.gif";	// PSA
		var p_prog_overview_chart_11_over = new Image (); p_prog_overview_chart_11_over.src = "/images/p_prog_overview_chart_11_over.gif";	// KS
		var p_prog_overview_chart_13_over = new Image (); p_prog_overview_chart_13_over.src = "/images/p_prog_overview_chart_13_over.gif";	// AS
		var p_prog_overview_chart_19_over = new Image (); p_prog_overview_chart_19_over.src = "/images/p_prog_overview_chart_19_over.gif";	// INF
		var p_prog_overview_chart_21_over = new Image (); p_prog_overview_chart_21_over.src = "/images/p_prog_overview_chart_21_over.gif";	// Toddler
		var p_prog_overview_chart_23_over = new Image (); p_prog_overview_chart_23_over.src = "/images/p_prog_overview_chart_23_over.gif";	// Preschooler
	}
	if (whichCategory == "campaign") {
		// set nav images to ON image
		var nav_campaign = '<img src="images/nav_campaign_on.gif" name="nav_camp" width="100" height="28" border="0">';
	}
	if (whichCategory == "event") {
		// set nav images to ON image
		var nav_event = '<img src="images/nav_event_on.gif" name="nav_event" width="100" height="28" border="0">';
	}
	if (whichCategory == "teacher") {
		// set nav images to ON image
		var nav_teacher = '<img src="images/nav_teacher_on.gif" name="nav_teacher" width="100" height="28" border="0">'
	}
	if (whichCategory == "trial") {
		// set nav images to ON image
		var nav_trial = '<img src="images/nav_trial_on.gif" name="nav_trial" width="100" height="28" border="0">';
	}
	if (whichCategory == "contact") {
	}
	if (whichCategory == "map") {
	}
	if (whichCategory == "pg") {
	}
	if (whichCategory == "ei_overview") {
		// set nav images to ON image
		var nav_ei_overview = '<img src="images/nav_ei_overview_over.gif" name="nav_ei_overview" width="100" height="28" border="0">';
		// set side background image randomly
//		Math.floor(Math.random()*Ｎ)
//		<td rowspan="3" background="images/bg_ei.jpg">&nbsp;</td>
/*
comment = new Array(3);
comment[0]="HTMLでホームページを作ろう！";
comment[1]="スタイルシートでデザインしよう！";
comment[2]="JavaScriptでページに動きをつけよう！";
n = Math.floor(Math.random()*3);
document.write(comment[n]);
*/
	}
	if (whichCategory == "ei_program") {
		// set nav images to ON image
		var nav_ei_program = '<img src="images/nav_ei_program_over.gif" name="nav_ei_program" width="100" height="28" border="0">';
	}
	if (whichCategory == "ei_faq") {
		// set nav images to ON image
		var nav_ei_faq = '<img src="images/nav_ei_faq_over.gif" name="nav_ei_faq" width="100" height="28" border="0">';
	}
	if (whichCategory == "ei_campaign") {
		// set nav images to ON image
		var nav_ei_campaign = '<img src="images/nav_ei_campaign_over.gif" name="nav_ei_campaign" width="100" height="28" border="0">';
	}
}