Image1 = new Image(428,115)
Image1.src = "images/abackgr0a.gif"   
Image2 = new Image(428,115)  
Image2.src = "images/abackgr0a.gif"    

function showmap() {  
document.marimage.src = Image2.src; return true;  
}    

function hidemap() {  
document.marimage.src = Image1.src; return true;  
}