js禁用tab键

兼容火狐和IE的版本:

<script type="text/javascript">document.onkeydown=function(e){ var isie = (document.all) ? true:false; var key; var ev; if(isie){//IE浏览器  key = window.event.keyCode;  ev = window.event; }else{//火狐浏览器  key = e.which;  ev = e; }  if(key==9){//IE浏览器  if(isie){   ev.keyCode=0;   ev.returnValue=false;  }else{//火狐浏览器   ev.which=0;   ev.preventDefault();  } }};</script>