if (document.images)
   {
     headon= new Image(130,105);
     headon.src="./img/head_logo_hover.jpg";
     
     headoff= new Image(130,105);
     headoff.src="./img/head_logo.jpg";     
		 
     lefton= new Image(250,155);
     lefton.src="./img/web_head_left_hover.jpg";
     
     leftoff= new Image(250,155);
     leftoff.src="./img/web_head_left.jpg";  		 
		 }

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

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