function changeBack(page) {
	swirl = new Image();
	swirl.src = "/img/back_swirls" + (page + 1) + ".jpg";
	document.body.style.backgroundImage = 'url(/img/back_swirls' + (page + 1) + '.jpg)';
}

function changeBack_bedrijven(page) {
	swirl = new Image();
	swirl.src = "/img/back_swirls_bedrijf" + (page + 1) + ".jpg";
	document.body.style.backgroundImage = 'url(/img/back_swirls_bedrijf' + (page + 1) + '.jpg)';
}