function abbrev_help() {
    var theWindow =
	window.open('abbrevhelp.jsp','abbrevHelp',
		'height=600,width=450,scrollbars=1,status=1,resizable=1,toolbar=1');
    theWindow.focus();
}

var currentContent = 'home';
var currentTab = 'home_tab';
function show(target) {
  previous = document.getElementById(currentContent);
  previous.style.display = "none";

  var previousTab = document.getElementById(currentContent + "_tab");
  previousTab.className = "tab";

  current = document.getElementById(target);
  current.style.display = "block";
  currentContent = target;

  currentTab = document.getElementById(target + '_tab');
  currentTab.className = "tab_active";
}