// JavaScript Document
if (document.images) {            
img1on = new Image();           
img1on.src = "images/res_sub_button1_on.gif"; 
img2on = new Image();
img2on.src = "images/res_sub_button2_on.gif";  
img3on = new Image();
img3on.src = "images/res_sub_button3_on.gif";
img4on = new Image();
img4on.src = "images/res_sub_button4_on.gif";

img1off = new Image();           
img1off.src = "images/res_sub_button1_off.gif"; 
img2off = new Image();
img2off.src = "images/res_sub_button2_off.gif";  
img3off = new Image();
img3off.src = "images/res_sub_button3_off.gif";
img4off = new Image();
img4off.src = "images/res_sub_button4_off.gif";
  

 

function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");        }}
                        
function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");        }}
}