function ChangeBgdImg(id) {

 if(id=="img1") { document.getElementById(id).style.backgroundImage = "url(images/banner-left-over_1.jpg)"; } 
  if(id=="img2") { document.getElementById(id).style.backgroundImage = "url(images/banner-left-over_2.jpg)"; } 
   if(id=="img3") { document.getElementById(id).style.backgroundImage = "url(images/banner-left-over_3.jpg)"; } 
}
function ChangeBgdImg2(id) {
 if(id=="img1") { document.getElementById(id).style.backgroundImage = "url(images/banner-left_1.jpg)"; } 
  if(id=="img2") { document.getElementById(id).style.backgroundImage = "url(images/banner-left_2.jpg)"; } 
   if(id=="img3") { document.getElementById(id).style.backgroundImage = "url(images/banner-left_3.jpg)"; } 
}