function cellOver(obj){
  document.getElementById("tr"+obj).style.backgroundImage="url(images/sbgorange.gif)";
}

function cellOut(obj){
  document.getElementById("tr"+obj).style.backgroundImage="url(images/sbg.gif)";
}

function cellOuty(obj){
  document.getElementById("tr"+obj).style.backgroundImage="url(images/sbg.gif)";
}