var tPopWait=50;
var tPopShow=99999;
var showPopStep=20;
var popOpacity=99;
var sPop=null;
var curShow=null;
var tFadeOut=null;
var tFadeIn=null;
var tFadeWaiting=null;
document.write("<div id='dypopLayer' style='position:absolute;z-index:1000;border: 1px solid #CDCDCD;padding:1px;filter: Alpha(Opacity=2);background-color: #FFF;color:#990;text-align:left;width:auto;'></div>");//class='cpoptext'
function showPopupText(){var o=event.srcElement;MouseX=event.x;MouseY=event.y;
if(o.alt!=null && o.alt!=""){o.dypop=o.alt;o.alt=""};if(o.title!=null && o.title!=""){o.dypop=o.title;o.title=""};
if(o.dypop!=sPop){sPop=o.dypop;
clearTimeout(curShow);clearTimeout(tFadeOut);clearTimeout(tFadeIn);clearTimeout(tFadeWaiting);
if(sPop==null || sPop=="") {dypopLayer.innerHTML="";dypopLayer.style.filter="Alpha()";dypopLayer.filters.Alpha.opacity=0;}
else {if(o.dyclass!=null) popStyle=o.dyclass 
else popStyle="cPopText";
curShow=setTimeout("showIt()",tPopWait);
}}}
function showIt(){dypopLayer.className=popStyle;dypopLayer.innerHTML=sPop;popWidth=dypopLayer.clientWidth;popHeight=dypopLayer.clientHeight;
if(MouseX+12+popWidth>document.body.clientWidth) popLeftAdjust=-popWidth-24
else popLeftAdjust=0;
if(MouseY+12+popHeight>document.body.clientHeight) popTopAdjust=-popHeight-24
else popTopAdjust=0;
dypopLayer.style.left=MouseX+12+document.body.scrollLeft+popLeftAdjust;dypopLayer.style.top=MouseY+12+document.body.scrollTop+popTopAdjust;dypopLayer.style.filter="Alpha(Opacity=0)";fadeOut();
}
function fadeOut(){if(dypopLayer.filters.Alpha.opacity<popOpacity) {dypopLayer.filters.Alpha.opacity+=showPopStep;tFadeOut=setTimeout("fadeOut()",1);} else {dypopLayer.filters.Alpha.opacity=popOpacity;tFadeWaiting=setTimeout("fadeIn()",tPopShow);}}
function fadeIn(){if(dypopLayer.filters.Alpha.opacity>0) {dypopLayer.filters.Alpha.opacity-=1;tFadeIn=setTimeout("fadeIn()",1);}}
document.onmouseover=showPopupText;

// 显示隐藏层 ONMOUSEOVER & ONMOUSEOUT 效果
<!--
function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_showHideLayers() { //v6.0
  var i,p,v,obj,args=MM_showHideLayers.arguments;
  for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];
    if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v=='hide')?'hidden':v; }
    obj.visibility=v; }
}
//-->

function subm()
{
  if (document.login.uname.value == "")
  {
    alert("请输入用户名");
	document.login.uname.focus();
	return false;
  }
  if (document.login.password.value == "")
  {
    alert("请输入密码");
	document.login.password.focus();
	return false;
  }
    if (document.login.password.value.length < 6)
  {
    alert("密码不能小于6位");
	document.login.password.focus();
	return false;
  }
     if (document.login.D1.value == "")
  {
  document.login.method="post";
  document.login.action="http://mail.it163.net:8383/login.cgi";
  document.login.userid.value = document.login.uname.value + "@" + document.login.uname2.value;
  document.login.passwd.value = document.login.password.value;
  document.login.submit();
  }
}