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        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;