var but_on = new Array(4);
var but_off = new Array(4);

function loadImages() {
if (document.images) {
  but_on[1] =new Image();  but_on[1].src ="images/nav_home1s.jpg"; 
  but_off[1]=new Image();  but_off[1].src="images/nav_home1.jpg"; 

  but_on[2] =new Image();  but_on[2].src ="images/nav_menu1s.jpg"; 
  but_off[2] =new Image();  but_off[2].src="images/nav_menu1.jpg"; 

  but_on[3] =new Image();  but_on[3].src ="images/nav_hours1s.jpg"; 
  but_off[3] =new Image();  but_off[3].src="images/nav_hours1.jpg"; 
}

}

function handleOver(buttonId) {
 if (document.images) document.getElementById(buttonId).src=but_on[buttonId].src;
}

function handleOut(buttonId) {
 if (document.images) document.getElementById(buttonId).src=but_off[buttonId].src;
}