function resize() { 
	var sidebarhoogte = document.getElementById('sidebar').offsetHeight;
	var contenthoogte = document.getElementById('article').offsetHeight;
	var navhoogte = document.getElementById('header').offsetHeight;
	if (contenthoogte > sidebarhoogte) {
		var max = contenthoogte;
	} else {
		var max = sidebarhoogte;
	}
	if (navhoogte-110 > max) {
		var hoogte = navhoogte-100;
	} else {
		var hoogte = max + 24;
		document.getElementById('backtotop').style.visibility = "visible";
	}
	document.getElementById('gradient_left').style.height = hoogte+'px';
	document.getElementById('gradient_left').style.height = hoogte+'px';
	document.getElementById('gradient_center').style.height = hoogte+'px';
	document.getElementById('gradient_right').style.height = hoogte+'px';
	document.getElementById('stripes_left').style.height = hoogte+'px';
	document.getElementById('stripes_center').style.height = hoogte+'px';
	document.getElementById('stripes_right').style.height = hoogte+'px';

	var anchors = document.getElementsByTagName('a');
	for (var i=0;i<=anchors.length;i++) {
		if (anchors[i] != undefined) {
			anchors[i].setAttribute('onfocus', 'this.blur()');
		}
	}
}
function showmenu(item) {
	document.getElementById('submenu_'+item).style.visibility = "visible";
} 
function hidemenu(item) {
	document.getElementById('submenu_'+item).style.visibility = "hidden";
}