js鼠标移动显示图片的简单实例_javascript技巧

//***********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<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;