/**
 * insert image advertisement depending on javascript cookie variable value
 * 
 * @return
 */
function advImage() {
	if (document.getElementById('adv')) {
		// get image cookie
		var cookie_img = getCookie('adv_img');

		// check image cookie
		if (!cookie_img) {
			document.getElementById('adv').src = '../images/web2.jpg';
			changeLinkSrc('link', '#');
		} else if (cookie_img == 'web_design') {
			document.getElementById('adv').src = '../images/design.jpg';
			changeLinkSrc('link', 'page.php?page_id=56');
		} else if (cookie_img == 'web_development') {
			document.getElementById('adv').src = '../images/developer.jpg';
			changeLinkSrc('link', 'page.php?page_id=55');
		} else if (cookie_img == 'print_design') {
			document.getElementById('adv').src = '../images/identity.jpg';
			changeLinkSrc('link', 'page.php?page_id=57');
		}
	}
}
function changeAdvImage(adv_type) {
	// create javascript expire date
	todayDate = new Date();
	expire = todayDate.getTime() + 3600;

	// animate and change advertise image depend on type
	if (adv_type == 'web_design') {
		$('#adv').fadeOut('slow');
		changeLinkSrc('link', 'page.php?page_id=56');
		setTimeout("changeImageSrc('adv','../images/design.jpg')", 1000);
		setTimeout("$('#adv').fadeIn('slow')", 1500);

		// set adv image cookie
		setcookie('adv_img', 'web_design', expire);
	}
	if (adv_type == 'web_development') {
		$('#adv').fadeOut('slow');
		changeLinkSrc('link', 'page.php?page_id=55');
		setTimeout("changeImageSrc('adv','../images/developer.jpg')", 1000);
		setTimeout("$('#adv').fadeIn('slow')", 1500);

		// set adv image cookie
		setcookie('adv_img', 'web_development', expire);
	}
	if (adv_type == 'print_design') {
		$('#adv').fadeOut('slow');
		changeLinkSrc('link', 'page.php?page_id=57');
		setTimeout("changeImageSrc('adv','../images/identity.jpg')", 1000);
		setTimeout("$('#adv').fadeIn('slow')", 1500);

		// set adv image cookie
		setcookie('adv_img', 'print_design', expire);
	}
}