screenX clientX pageX的区别

screenX clientX pageX概念

screenX:鼠标位置相对于用户屏幕水平偏移量，而screenY也就是垂直方向的，此时的参照点也就是原点是屏幕的左上角。

clientX:跟screenX相比就是将参照点改成了浏览器内容区域的左上角，该参照点会随之滚动条的移动而移动。

pageX：参照点也是浏览器内容区域的左上角，但它不会随着滚动条而变动

如图(红点就是鼠标当前位置)

参考代码

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <script type="text/javascript" src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
    <style>
        body {
            margin: 0;
            padding: 0;
        }
        .div {
            text-align: center;
            font-size: 24px;
            height: 300px;
            width: 1300px;
            line-height: 300px;
            color: yellow;
        }

        #d1 {
            background-color: red;
        }

        #d2 {
            background-color: green;

        }

        #d3 {
            background-color: blue;
        }

        #d4 {
            position: absolute;
            background-color: yellow;
            height: 150px;
            width: 120px;
            top: 0;
        }
    </style>
    <script type="text/javascript">

        $(function () {

            window.onscroll = function () {
                $("#d4").css("top", getScrollTop());
            };

            document.onmousemove = function (e) {
                if (e == null) {
                    e = window.event;
                }
                var html = "screenX:" + e.screenX + "<br/>";
                html += "screenY:" + e.screenY + "<br/><br/>";
                html += "clientX:" + e.clientX + "<br/>";
                html += "clientY:" + e.clientY + "<br/><br/>";
                if (e.pageX == null) {
                    html += "pageX:" + e.x + "<br/>";
                    html += "pageY:" + e.y + "<br/>";
                } else {
                    html += "pageX:" + e.pageX + "<br/>";
                    html += "pageY:" + e.pageY + "<br/>";
                }

                $("#d4").html(html);
            };
        });

        function getScrollTop() {
            var top = (document.documentElement && document.documentElement.scrollTop) ||
              document.body.scrollTop;
            return top;
        }
    </script>
</head>
<body>
    <div id="d1" class="div">div1 height:300px width:1300px</div>
    <div id="d2" class="div">div2 height:300px width:1300px</div>
    <div id="d3" class="div">div3 height:300px width:1300px</div>
    <div id="d4"></div>
</body>
</html>