js 实现鼠标按下 拖动div

</pre><pre name="code" class="javascript">//div 拖动 div的IDcontainer.onmousedown = function() {//获取鼠标当前坐标 var pageX = event.clientX;var pageY = event.clientY;//获取block的坐标，左边界和上边界 var offX = parseInt(this.style.left) || 0;var offY = parseInt(this.style.top) || 0;//计算出鼠标坐标相对于block坐标的间距 var offLX = pageX - offX;var offLY = pageY - offY;if (!document.onmousemove) {document.onmousemove = function() {container.style.left = event.clientX - offLX; //设置block的X坐标 container.style.top = event.clientY - offLY; //设置block的Y坐标 }}}document.onmouseup = function() {document.onmousemove = null;} //鼠标弹起 //div 拖动