{  
	//////////////////////// preload on images
      
 // negative button
		negativeon = new Image(150,15);
		negativeon.src = "negative_on.jpg";	

	
	//////////////////////// preload off images
 
 
 // negative button
		negativeoff = new Image(150,15);
		negativeoff.src = "negative_off.jpg";	
	

		
} 

// mouseover event for on images
	function img_act(imgName)  {
	    imgOn = eval(imgName + "on.src");
	    document [imgName].src = imgOn;      
	}

// mouseover event for off images
	function img_inact(imgName) {
    imgOff = eval(imgName + "off.src");
    document [imgName].src = imgOff;
	}