function IsDefined(myVar) {
	var undefined;
	if (myVar != undefined) {
		return true;
	} else {
		return false;
	}
}

function OpenVenster(url,width,height,left_pos,top_pos) {
	if (!(IsDefined(width))) {
		width=580;
	}
	if (!(IsDefined(height))) {
		height=580;
	}
	if (!(IsDefined(left_pos))) {
		left_pos = (screen.availWidth/2) - (width / 2);
	}
	if (!(IsDefined(top_pos))) {
		top_pos = (screen.availHeight/2) - (height / 2);
	}
	newWindow = window.open( url,"openvensterwindow","height=" + height + ",left=" + left_pos + ",scrollbars=yes,status=no,resizable=no,toolbar=no,top=" + top_pos + ",width="+width + ",height=" + height);
}

function viewimage(afbeelding, categorie) {
  OpenVenster('image.php?img=' + afbeelding + '&cat=' + categorie,660,600,((screen.availWidth/2) - (350/2)),((screen.availHeight/2) - (350/2)));
}
document.write('<script language="javascript" src="include/chromeless_35.js"></scr'+'ipt>');