function toggle(div_id) {
	var el = document.getElementById(div_id);
	if ( el.style.display == 'none' ) {	el.style.display = 'block';}
	else {el.style.display = 'none';}
}
function blanket_size(popUpDivVar,pop_up_height_post) {
	if (typeof window.innerWidth != 'undefined') {
		viewportheight = window.innerHeight;
	} else {
		viewportheight = document.documentElement.clientHeight;
	}
	if ((viewportheight > document.body.parentNode.scrollHeight) && (viewportheight > document.body.parentNode.clientHeight)) {
		blanket_height = viewportheight;
	} else {
		if (document.body.parentNode.clientHeight > document.body.parentNode.scrollHeight) {
			blanket_height = document.body.parentNode.clientHeight;
		} else {
			blanket_height = document.body.parentNode.scrollHeight;
		}
	}
	var blanket = document.getElementById('blanket');
	blanket.style.height = blanket_height + 'px';
	var popUpDiv = document.getElementById(popUpDivVar);
	popUpDiv_height=blanket_height/2-pop_up_height_post/2; 

	popUpDiv.style.top = popUpDiv_height + 'px';
	
}
function window_pos(popUpDivVar,pop_up_width_post) {
	if (typeof window.innerWidth != 'undefined') {
		viewportwidth = window.innerHeight;
	} else {
		viewportwidth = document.documentElement.clientHeight;
	}
	if ((viewportwidth > document.body.parentNode.scrollWidth) && (viewportwidth > document.body.parentNode.clientWidth)) {
		window_width = viewportwidth;
	} else {
		if (document.body.parentNode.clientWidth > document.body.parentNode.scrollWidth) {
			window_width = document.body.parentNode.clientWidth;
		} else {
			window_width = document.body.parentNode.scrollWidth;
		}
	}
	var popUpDiv = document.getElementById(popUpDivVar);
	window_width=window_width/2-pop_up_width_post/1.3;  
	popUpDiv.style.left = window_width + 'px';
}

function popup(windowname,cookiename,pop_up_height,pop_up_width) {

	var cookie_var = readCookie(cookiename)
	if (!cookie_var) {
		blanket_size(windowname,pop_up_height);
		window_pos(windowname,pop_up_width);
		toggle('blanket');
		toggle(windowname);			
	}
	createCookie(cookiename,'gezien',7)	
	
}

function popup_close(windowname) {
	toggle('blanket');
	toggle(windowname);			
}


function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function eraseCookie(name) {
	createCookie(name,"",-1);
}