function change_bg(nav_item) {
	var oFor = document.getElementById("for");
	if (oFor == null) {
		return;
	}
	
	if (nav_item == 'm-thuis') {
		oFor.style.backgroundImage = "url(/Mijn/img/bg_thuis1.gif)";
		//alert(oFor.className);
		oFor.className = "for thuis";
		//alert(oFor.className);
	}
	else if (nav_item == 'm-install') {
		oFor.style.backgroundImage = "url(/Mijn/img/bg_installers.gif)";
		oFor.className = "for";
	}
	else if (nav_item == 'm-businessp') {
		oFor.style.backgroundImage = "url(/Mijn/img/bg_businesspartners.gif)";
		oFor.className = "for businesspartners";
	}
}