function categorySetup() {
  document.getElementById("category-submit").style.display = "none";
  var opt = document.getElementById("category-chooser");
  showCategory(opt.options[opt.selectedIndex].value);
}

function showCategory(catNum) {
  var catName = "-"+catNum+"-";
  var nodes = document.getElementsByTagName("DIV");
  for (var i = 0; i < nodes.length; i++) {
    var nodeObj = nodes.item(i);
	var className = nodeObj.className;
	if (className.indexOf("categories-") > -1) {
	  nodeObj.style.display = className.indexOf(catName) > -1 ? "block" : "none";
	}
  }
}