if (document.images) { 

var img1on = new Image();
img1on.src = "images/btn_company_on.gif";
var img1off = new Image();
img1off.src = "images/btn_company.gif";

var img2on = new Image();
img2on.src = "images/btn_inquiry_on.gif";
var img2off = new Image();
img2off.src = "images/btn_inquiry.gif";

var img3on = new Image();
img3on.src = "images/navi_home_on.gif";
var img3off = new Image();
img3off.src = "images/navi_home.gif";

var img4on = new Image();
img4on.src = "images/navi_brand_on.gif";
var img4off = new Image();
img4off.src = "images/navi_brand.gif";

var img5on = new Image();
img5on.src = "images/navi_web_on.gif";
var img5off = new Image();
img5off.src = "images/navi_web.gif";

var img6on = new Image();
img6on.src = "images/navi_medical_on.gif";
var img6off = new Image();
img6off.src = "images/navi_medical.gif";

} 


function On(name) { 

if (document.images) { 
document.images[name].src = eval(name + 'on.src'); 
} 

} 


function Off(name) { 

if (document.images) { 
document.images[name].src = eval(name + 'off.src'); 
} 

}