典型特效

var pltsPop=null;
var pltsoffsetX = 5;   // 弹出窗口位于鼠标左侧或者右侧的距离；3-12 合适
var pltsoffsetY = 5;  // 弹出窗口位于鼠标下方的距离；3-12 合适
var pltsPopbg="#FFffff"; //背景色
var pltsPopfg="#880000"; //前景色
var pltsTitle="";
document.write('<div id=pltsTipLayer style="display: none;position: absolute; z-index:10001"></div>');
function pltsinits()
{
    document.onmouseover   = plts;
    document.onmousemove = moveToMouseLoc;
}
function plts()
{  var o=event.srcElement;
    if(o.alt!=null && o.alt!=""){o.dypop=o.alt;o.alt=""};
    if(o.title!=null && o.title!=""){o.dypop=o.title;o.title=""};
    pltsPop=o.dypop;
    if(pltsPop!=null&&pltsPop!=""&&typeof(pltsPop)!="undefined")
    {
pltsTipLayer.style.left=-20;
pltsTipLayer.style.display='';
var Msg=pltsPop.replace(/\n/g,"<br>");
Msg=Msg.replace(/\0x13/g,"<br>");
var re=https://www.jb51.net/\{(.[^\{]*)\}/ig;
if(!re.test(Msg))pltsTitle="";
else{
   re=https://www.jb51.net/\{(.[^\{]*)\}(.*)/ig;
     pltsTitle=Msg.replace(re,"$1")+"&nbsp;";
   re=https://www.jb51.net/\{(.[^\{]*)\}/ig;
   Msg=Msg.replace(re,"");
   Msg=Msg.replace("<br>","");}
   var attr=(document.location.toString().toLowerCase().indexOf("")>0?"nowrap":"");
        var content =
       '<table style="FILTER:alpha(opacity=90) shadow(color=#6f6f6f,direction=135);" id=toolTipTalbe ><tr><td width="100%"><table class=tdr cellspacing="0" cellpadding="0" border=0 style="width:100%">'+
       '<tr id=pltsPoptop ><th height=25 valign=bottom  class=tdr><p id=topleft align=left>'+pltsTitle+'</p><p id=topright align=right style="display:none">'+pltsTitle+'</th></tr>'+
       '<tr><td "+attr+" class=bg_tdr style="padding-left:14px;padding-right:14px;padding-top: 6px;padding-bottom:6px;line-height:135%">'+Msg+'</td></tr>'+
       '<tr id=pltsPopbot style="display:none"><th height=25 valign=bottom class=tdr><p id=botleft align=left>'+pltsTitle+'</p><p id=botright align=right style="display:none">'+pltsTitle+'</th></tr>'+
       '</table></td></tr></table>';
        pltsTipLayer.innerHTML=content;
        toolTipTalbe.style.width=Math.min(pltsTipLayer.clientWidth,document.body.clientWidth/2.2);
        moveToMouseLoc();
        return true;
       }
    else
    {
     pltsTipLayer.innerHTML='';
       pltsTipLayer.style.display='none';
        return true;
    }
}

function moveToMouseLoc()
{
if(pltsTipLayer.innerHTML=='')return true;
var MouseX=event.x;
var MouseY=event.y;
//window.status=event.y;
var popHeight=pltsTipLayer.clientHeight;
var popWidth=pltsTipLayer.clientWidth;
if(MouseY+pltsoffsetY+popHeight>document.body.clientHeight)
{
    popTopAdjust=-popHeight-pltsoffsetY*1.5;
    pltsPoptop.style.display="none";
    pltsPopbot.style.display="";
}
  else
{
     popTopAdjust=0;
    pltsPoptop.style.display="";
    pltsPopbot.style.display="none";
}
if(MouseX+pltsoffsetX+popWidth>document.body.clientWidth)
{
  popLeftAdjust=-popWidth-pltsoffsetX*2;
  topleft.style.display="none";
  botleft.style.display="none";
  topright.style.display="";
  botright.style.display="";
}
else
{
  popLeftAdjust=0;
  topleft.style.display="";
  botleft.style.display="";
  topright.style.display="none";
  botright.style.display="none";
}
pltsTipLayer.style.left=MouseX+pltsoffsetX+document.body.scrollLeft+popLeftAdjust;
pltsTipLayer.style.top=MouseY+pltsoffsetY+document.body.scrollTop+popTopAdjust;
   return true;
}
pltsinits();