js鼠标移动在title中显示图片的效果代码

//***********默认设置定义.*********************
tPopWait=50;//停留tWait豪秒后显示提示。
tPopShow=5000;//显示tShow豪秒后关闭提示
showPopStep=20;
popOpacity=99;

//***************内部变量定义*****************
sPop=null;
curShow=null;
tFadeOut=null;
tFadeIn=null;
tFadeWaiting=null;

document.write("");
document.write("");


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        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;