{ 
image1a = new Image(); 
image1a.src = "images/email_off.jpg"; 

image1b = new Image(); 
image1b.src = "images/email_on.jpg"; 
} 

function overImg(objName){ 

                imgSrc = eval(objName + "b.src"); 
                document[objName].src = imgSrc; 
} 

function outImg(objName){ 

                imgSrc = eval(objName + "a.src"); 

                document[objName].src = imgSrc; 
  
}