按下鼠标进行拖拽，让元素跟随鼠标进行移动，鼠标抬起，元素停止移；js鼠标拖拽 （鼠标按下事件：onmousedown、鼠标移动事件：onmousemove、鼠标抬起事件：onmouseup）
需求如下：
按下鼠标进行拖拽，让元素跟随鼠标进行移动，鼠标抬起，元素停止移动。
解析：
鼠标按下事件：onmousedown
鼠标移动事件：onmousemove
鼠标抬起事件：onmouseup
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><style>#chatFrame{width: 300px;height: 300px;position: absolute;}</style>
</head>
<body><div id="chatFrame" style="width: 300px;height: 300px;background-color: yellowgreen;"></div><script>var div = document.getElementById("chatFrame");var isDragging = false; // 用于标识是否正在拖拽// 鼠标按下事件div.onmousedown = function(event) {isDragging = false; // 每次鼠标按下时重置拖拽标识if (div.setCapture !== undefined) {div.setCapture();}var disX = event.clientX - div.offsetLeft;var disY = event.clientY - div.offsetTop;// 鼠标移动事件document.onmousemove = function(event) {isDragging = true; // 如果发生了移动，认为发生了拖拽var x = event.clientX - disX;var y = event.clientY - disY;div.style.left = x + 'px';div.style.top = y + 'px';};// 鼠标抬起事件document.onmouseup = function() {if (div.releaseCapture !== undefined) {div.releaseCapture();}document.onmousemove = null;// 如果没有发生拖拽，则执行点击事件的默认行为if (!isDragging) {handleIm();}};return false; // 阻止默认行为};// 鼠标点击事件处理函数function handleIm() {console.log("Handle click event");// 在这里添加你希望执行的点击事件的逻辑}</script>
</body>
</html>