function HoverIn(obj){
	document.getElementById(obj).style.backgroundImage = 'url(/images/menu_hover.png)';
}

function HoverOut(obj){
	switch(obj){
		case 'menu_a':
			document.getElementById(obj).style.backgroundImage = 'url(/images/menu_main.png)';
		break;
	
		case 'menu_b':
			document.getElementById(obj).style.backgroundImage = 'url(/images/menu_about.png)';
		break;
	
		case 'menu_c':
			document.getElementById(obj).style.backgroundImage = 'url(/images/menu_add.png)';
		break;
	
		case 'menu_d':
			document.getElementById(obj).style.backgroundImage = 'url(/images/menu_contact.png)';
		break;
	
		case 'menu_e':
			document.getElementById(obj).style.backgroundImage = 'url(/images/menu_adv.png)';
		break;
	}
}