var image_tree_plus = new Image();
image_tree_plus.src = "/img/_plus.gif";

var image_tree_minus = new Image();
image_tree_minus.src = "/img/_minus.gif";

function ClickBranch(BranchId, ImageId){

  eTargetTable = document.getElementById(BranchId)
  eTargetImage = document.getElementById(ImageId)

  if ( eTargetTable.style.display == "none" ){
    eTargetTable.style.display = "block";
    eTargetImage.src           = image_tree_minus.src; 
  }
  else{
    eTargetTable.style.display = "none"
    eTargetImage.src           = image_tree_plus.src; 
  }
}