lovecoding
/
W260426


			
				
					
						
						
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							<!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>
        .box{
            width: 100px;
            height: 100px;
            background-color: red;
            position: fixed;
            top:0;
            left:0;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <script>
        // 获取元素
        var box = document.querySelector(".box");
        // 获取整个文档
        var doc = document.documentElement;
        // 绑定事件
        box.onmousedown = function(e){
            // 元素距离顶部的距离
            var docTop = box.offsetTop;
            // 元素距离左侧的距离
            var docLeft = box.offsetLeft;
            // 鼠标点击的位置距离顶部的间距
            var mouseTop = e.clientY;
            // 鼠标点击的位置距离左侧的间距
            var mouseLeft = e.clientX;
            // 获取鼠标点击位置距离元素顶部的间距
            var resTop = mouseTop - docTop;
            // 获取鼠标点击位置距离元素左侧的间距
            var resLeft = mouseLeft - docLeft;
            // 给整个文档绑定移动事件
            doc.onmousemove = function(event){
                // 拖动时 正方形的位置会改变
                box.style.left = event.clientX - resLeft + "px";
                box.style.top = event.clientY - resTop + "px";
            }

        }
        // 给整个文档绑定鼠标松开事件
        doc.onmouseup = function(){
            // 鼠标松开时 正方形停止移动
            doc.onmousemove = null;
        }
    </script>
</body>
</html>