JAVA & XML & JAVASCRIPT & AJAX & CSS

<script>
function window.onhelp() {//屏蔽F1帮助
return false}
function document.onkeydown() {
 if (event.keyCode==116) {//屏蔽F5键
  event.keyCode = 0;
  event.cancelBubble = true;
  return false;
 }
 if (event.keyCode==122) {//屏蔽F11键
  event.keyCode = 0;
  event.cancelBubble = true;
  return false;
 }
 if ((event.ctrlKey && event.keyCode==82)) {//屏蔽Ctrl+R
  event.keyCode = 0;
  event.cancelBubble = true;
  return false;
 }
 if ((event.ctrlKey && event.keyCode==78)) {//屏蔽Ctrl+N
  event.keyCode = 0;
  event.cancelBubble = true;
  return false;
 }
 if ((event.keyCode == 8) && (event.srcElement.type != "text" && event.srcElement.type != "textarea" && event.srcElement.type != "password")) {//屏蔽BackSpace键
  event.keyCode = 0;
  event.cancelBubble = true;
  return false;
 }
}</script>