JAVASCRIPT 如何停止图片轮回

//自动轮播效果
var itv=setInterval(function(){
if(targetIdx targetIdx++;
}else{
targetIdx=0;
}
self.fade(targetIdx,curIndex);
curIndex=targetIdx;
},5000);
id(ulId).onmouseover=function(){ clearInterval(itv)};
id(ulId).onmouseout=function(){
itv=setInterval(function(){
if(targetIdx targetIdx++;
}else{
targetIdx=0;
}
self.fade(targetIdx,curIndex);
curIndex=targetIdx;
},5000);
}
},

我想让鼠标放到图片上时停止轮回。。该怎么弄。。。求大神

var scroll = true;
var scrollHandler = function(){
    if(scroll){
if(targetIdx targetIdx++;
}else{
targetIdx=0;
}
self.fade(targetIdx,curIndex);
curIndex=targetIdx;
}
}

setInterval(scroll,5000);

id(ulId).onmouseover=function(){ 
scroll = true;
};
id(ulId).onmouseout=function(){
scroll = false;
}

虽然我很聪明，但这么说真的难到我了