<style type="text/css">
    div{
        width:200px;
        height:200px;
        background:#EEE;
    }
    #two{
        position:absolute;
        left:100px;
        top:50px;
        background:#F60;
    }
</style>
<div id="one">One</div>
<div id="two">Two</div>
<div id="three">Three</div>
<script>
    console.log(isOverlap("one","two"));//true
    console.log(isOverlap("one","three"));//false
    console.log(isOverlap("two","three"));//true
    function isOverlap(idOne,idTwo){
        var objOne=$("#"+idOne),
            objTwo=$("#"+idTwo),
            offsetOne = objOne.offset(),
            offsetTwo = objTwo.offset(),
            topOne=offsetOne.top,
            topTwo=offsetTwo.top,
            leftOne=offsetOne.left,
            leftTwo=offsetTwo.left,
            widthOne = objOne.width(),
            widthTwo = objTwo.width(),
            heightOne = objOne.height(),
            heightTwo = objTwo.height();
        var leftTop = leftTwo > leftOne && leftTwo < leftOne+widthOne 
                && topTwo > topOne && topTwo < topOne+heightOne,
            rightTop = leftTwo+widthTwo > leftOne && leftTwo+widthTwo < leftOne+widthOne 
                && topTwo > topOne && topTwo < topOne+heightOne,
            leftBottom = leftTwo > leftOne && leftTwo < leftOne+widthOne 
                && topTwo+heightTwo > topOne && topTwo+heightTwo < topOne+heightOne,
            rightBottom = leftTwo+widthTwo > leftOne && leftTwo+widthTwo < leftOne+widthOne 
                && topTwo+heightTwo > topOne && topTwo+heightTwo < topOne+heightOne;
        return leftTop || rightTop || leftBottom || rightBottom;
    }
</script>