window.onload = load_function;
window.onresize = dynamic_height;

var pages;
var currentpage;

function load_function() {
	dynamic_height();
}

function obj_height(id) {
	return(document.getElementById(id).offsetHeight);
}

function obj_width(id) {
	return(document.getElementById(id).offsetWidth);
}

function use(id) {
	return(document.getElementById(id));
}

/*
   name - name of the cookie
   value - value of the cookie
   [expires] - expiration date of the cookie
     (defaults to end of current session)
   [path] - path for which the cookie is valid
     (defaults to path of calling document)
   [domain] - domain for which the cookie is valid
     (defaults to domain of calling document)
   [secure] - Boolean value indicating if the cookie transmission requires
     a secure transmission
   * an argument defaults when it is assigned null as a placeholder
   * a null placeholder is not required for trailing omitted arguments
*/
function setCookie(name, value, expires, path, domain, secure) {
    expires_date = new Date(new Date().getTime() + expires)

	var curCookie = name + "=" + escape(value) +
		((expires) ? "; expires=" + expires_date.toGMTString() : "") +
		((path) ? "; path=" + path : "") +
		((domain) ? "; domain=" + domain : "") +
		((secure) ? "; secure" : "");

	document.cookie = curCookie;
}

/*
  name - name of the desired cookie
  return string containing value of specified cookie or null
  if cookie does not exist
*/
function getCookie(name) {
	var dc = document.cookie;
	var prefix = name + "=";
	var begin = dc.indexOf("; " + prefix);

	if (begin == -1) {
		begin = dc.indexOf(prefix);
	
		if (begin != 0) return null;
	} else
	    begin += 2;

		var end = document.cookie.indexOf(";", begin);

		if (end == -1)
			end = dc.length;

	return unescape(dc.substring(begin + prefix.length, end));
}

/*
   name - name of the cookie
   [path] - path of the cookie (must be same as path used to create cookie)
   [domain] - domain of the cookie (must be same as domain used to
     create cookie)
   path and domain default if assigned null or omitted if no explicit
     argument proceeds
*/
function deleteCookie(name, path, domain) {
	if (getCookie(name)) {
		document.cookie = name + "=" +
			((path) ? "; path=" + path : "") +
			((domain) ? "; domain=" + domain : "") +
			"; expires=Thu, 01-Jan-70 00:00:01 GMT";
	}
}

function dynamic_height() {
	use('middle_center').style.width = (document.documentElement.clientWidth - obj_width('middle_left') - obj_width('middle_right') - 120) + "px";

	var highest = Math.max(obj_height('middle_left'), obj_height('middle_center'), obj_height('middle_right'));

	if(highest < (document.documentElement.clientHeight - obj_height('top'))) {
		//drawn content is smaller then browser window
		var required_height = (document.documentElement.clientHeight - obj_height('top') - obj_height('footer'));

		use('middle_left').style.height = required_height + "px";
		use('middle_center').style.height = required_height + "px";
		use('middle_right').style.height = required_height + "px";

		use('footer').style.top = (required_height + obj_height('top')) + "px";
	} else {
		//drawn content is bigger then browser window

		use('middle_left').style.height = highest + "px";
		use('middle_center').style.height = highest + "px";
		use('middle_right').style.height = highest + "px";

		use('footer').style.top = (highest + obj_height('top')) + "px";
	}


	if(use('spacer') != null) {
		use('spacer').style.height = obj_height('logo_rechts_onder') + "px";
	}
}