if (document.images)
   {
     login_button1on= new Image(39,17);
     login_button1on.src="images/login_button1b.jpg";
     login_button2on= new Image(58,17);
     login_button2on.src="images/login_button2b.jpg"; 
     login_button3on= new Image(58,17);
     login_button3on.src="images/login_button3b.jpg";  
     button1on= new Image(70,68);
     button1on.src="images/button1b.jpg";  
     button2on= new Image(100,68);
     button2on.src="images/button2b.jpg";  
     button3on= new Image(89,68);
     button3on.src="images/button3b.jpg";  
     button4on= new Image(101,68);
     button4on.src="images/button4b.jpg";  
     button5on= new Image(106,68);
     button5on.src="images/button5b.jpg";  
                                                        
     login_button1off= new Image(39,17);
     login_button1off.src="images/login_button1a.jpg";
     login_button2off= new Image(58,17);
     login_button2off.src="images/login_button2a.jpg";            
     login_button3off= new Image(58,17);
     login_button3off.src="images/login_button3a.jpg"; 
     button1off= new Image(70,68);
     button1off.src="images/button1a.jpg"; 
     button2off= new Image(100,68);
     button2off.src="images/button2a.jpg"; 
     button3off= new Image(89,68);
     button3off.src="images/button3a.jpg"; 
     button4off= new Image(101,68);
     button4off.src="images/button4a.jpg"; 
     button5off= new Image(106,68);
     button5off.src="images/button5a.jpg"; 
   }

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

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