function stelAchtergrond() {
	var resHoogte = screen.height; 
	var resBreedte = screen.width; 
	
	if (resBreedte <= 1024) { 
		document.body.style.backgroundImage='url(/images/achtergrond/IMG_1024x768.gif)';
	} else if ((resBreedte >= 1024) && (resBreedte < 1280)) { 
		document.body.style.backgroundImage='url(/images/achtergrond/IMG_1280x1024.gif)';
	} else if (resBreedte >= 1280) { 
		document.body.style.backgroundImage='url(/images/achtergrond/IMG_1680x1050.gif)'; 
	}
}