imgAct = new Array();
imgOff = new Array();

function preloadImg(target,img_width,img_height) {

	if (document.images) {

		if (target == 'hyperlinks') {

			imgAct[target] = new Image(img_width,img_height);
			imgAct[target].src = '../img/nav_links_act.gif';
			imgOff[target] = new Image(img_width,img_height);
			imgOff[target].src = '../img/nav_links.gif';

		} else {

			imgAct[target] = new Image(img_width,img_height);
			imgAct[target].src = '../img/nav_' + target + '_act.gif';
			imgOff[target] = new Image(img_width,img_height);
			imgOff[target].src = '../img/nav_' + target + '.gif';

		}

	}

}

preloadImg('hajimeni',84,33);
preloadImg('ongaku',84,44);
preloadImg('yotei',51,55);
preloadImg('yomimono',101,36);
preloadImg('keijiban',77,53);
preloadImg('hyperlinks',58,52);

function activateImg(target) {

	if (document.images) {

		document[target].src = imgAct[target].src;

	}

}

function inactiveImg(target) {

	if (document.images) {

		if (target != current) {

			document[target].src = imgOff[target].src;

		} else {

			document[target].src = '../img/nav_' + target + '_on.gif';

		}

	}

}