lovecoding
/
W0407


			
				
					
						
						
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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: 300px;
            height: 300px;
            background: yellowgreen;
            cursor: pointer;
            margin-left: 20px;
            position: absolute;
            /* left: 300px; */
        }
    </style>
</head>
<body>
    <div id="box"></div>
    <script>
        var box = document.getElementById("box");
        box.onmousedown = function(event) {
            console.log(event)
            // event.clientX event.clintY 事件触发时 鼠标所在的X,Y坐标
            // 计算鼠标在元素内部的偏移量
            var left1 = event.clientX - box.offsetLeft;
            var top1 = event.clientY - box.offsetTop;

            // 移动事件 绑定给document
            document.onmousemove = function(event) {
                box.style.left = event.clientX - left1 + 'px';
                box.style.top = event.clientY - top1 + 'px';
            }
        }
        // 抬起事件
        document.onmouseup = function() {
            document.onmousemove = null;
        }
    </script>
</body>
</html>