某个元素在页面的偏移量

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #ss {
          position: absolute;
        top: 50px;
        left: 50px;
        width: 500px;
        height: 500px;
        background-color: blueviolet;
        }
        #box{
           
            margin-left: 20px;
            width:250px;height:300px;border:1px solid #e5e5e5;background:#f1f1f1;}

    </style>
   <script>
    window.onload = function(){
        var p = document.getElementById('box')
       
        function getElementLeft(element){
        var actualLeft = element.offsetLeft;
        var current = element.offsetParent;
        while (current !== null){
            actualLeft += current.offsetLeft;
            current = current.offsetParent;
}
        return actualLeft;
    }
    console.log(getElementLeft(p))
 function getElementTop(element){
    var actualTop = element.offsetTop;
    var current = element.offsetParent;
    while (current !== null){
        actualTop += current. offsetTop;
        current = current.offsetParent;
}
    return actualTop;
}
console.log(getElementTop(p))
    }

    
   </script>
</head>
<body>
   <div id="ss">
    <div id="box">
     

    </div>
   </div>
</body>
</html>