html源码：

    <divonMouseDown={(e) =>fn1(e)}onMouseUp={(e)=>fn2(e)}>内容</div>

js源码

  fn1(event) => {
//鼠标按下事件console.log('onMouseDown', event);
//鼠标按下时移动鼠标事件（鼠标未抬起）document.onmousemove = function (e) {console.log('onmousemove', e);};};fn2(event) => {
//清除鼠标移动事件document.onmousemove=null}

打印结果：