JavaScript DOM Event对象

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <style type="text/css">
        #areaDiv{
            width: 300px;
            height: 100px;
            border: solid 1px black;
        }
        #showMsg{
            width: 100px;
            height: 20px;
            border: solid 1px black;
        }
        #box1{
                width: 100px;
                height: 100px;
                background-color: red;
                /*
                 * 要设置偏移量left，top，要开启绝对定位
                 */
                position: absolute;
            }
    </style>
    <body>
        <div id="areaDiv"></div>
            <br />
        <div id="showMsg"></div>
        <div id="box1">
            
        </div>
    </body>
    <script type="text/javascript">
        /*当鼠标移动在areaDiv中，showMsg中显示鼠标坐标
         */
        var areaDiv=document.getElementById("areaDiv");
        var showMsg=document.getElementById("showMsg");
        //鼠标移动事件
        areaDiv.onmousemove=function(event){
//            alert("hello");
            //Event事件对象作为实参传入响应函数
            var x=event.clientX;
            var y=event.clientY;
            showMsg.innerHTML="x="+x+","+"y="+y;
        }
//        https://www.w3cschool.cn/jsref/dom-obj-event.html

        //#box1跟随鼠标移动
        var box1=document.getElementById("box1");
        document.onmousemove=function(event){
            //解决兼容性问题
            event=event||window.event;
            //css设置偏移量，坐标设置
             //clientX是相对可见窗口的坐标，有滚动条的时候雨div相对页面的坐标不对应，此时要有pagex
            box1.style.left=event.pageX+"px";
            box1.style.top=event.pageY+"px";
        }
    </script>
</html>
JavaScript DOM Event对象

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