<template>
	<div id="webId">
  	<div>你的web页面</div>
	  <!-- 1.1 如果碰到滑动问题，请检查这里是否属于同一点。 -->
	  <!-- 悬浮的HTML -->
	  <div class="xuanfu" id="moveDiv"
	   @mousedown="down()" @touchstart="down()"
	   @mousemove.prevent.stop="move()"
     @touchmove.prevent.stop="move()"
	   @mouseup="end()" @touchend="end()"
	  >
	   <div class="yuanqiu">11</div>
	  </div>
	</div>
</template>

<script>
data() {
 return {
  flags: false,
  position: { x: 0, y: 0 },
  nx: '', ny: '', dx: '', dy: '', xPum: '', yPum: '',
 }
}

methods: {
 // 实现移动端拖拽
 down(){
  this.flags = true;
  let touch;
  if(event.touches){
    touch = event.touches[0];
  }else {
    touch = event;
  }
  this.position.x = touch.clientX;
  this.position.y = touch.clientY;
  this.dx = moveDiv.offsetLeft;
  this.dy = moveDiv.offsetTop;
 },
 move(){
  if(this.flags){
   let touch ;
   if(event.touches){
     touch = event.touches[0];
   }else {
     touch = event;
   }
   this.nx = touch.clientX - this.position.x;
   this.ny = touch.clientY - this.position.y;
   this.xPum = this.dx+this.nx;
   this.yPum = this.dy+this.ny;
   //添加限制：只允许在屏幕内拖动
	 const maxWidth = document.body.clientWidth - 54;//屏幕宽度减去悬浮框宽高
	 const maxHeight = document.body.clientHeight - 54;
	 if (this.xPum < 0) { //屏幕x限制
		this.xPum = 0;
	 } else if (this.xPum>maxWidth) {
	  this.xPum = maxWidth;
	 }
	 if (this.yPum < 0) { //屏幕y限制
		this.yPum = 0;
	 } else if (this.yPum>maxHeight) {
		this.yPum = maxHeight;
	 }
   moveDiv.style.left = this.xPum+"px";
   moveDiv.style.top = this.yPum +"px";
   //阻止页面的滑动默认事件
   document.addEventListener("touchmove",function(){ // 1.2 如果碰到滑动问题，请注意是否获取到 touchmove
     event.preventDefault();//jq 阻止冒泡事件
     // event.stopPropagation(); // 如果没有引入jq 就用 stopPropagation()
   },false);
  }
 },
//鼠标释放时候的函数
 end(){
  this.flags = false;
 },
}
</script>

<style>
 /*css样式可自定义 仅提供参考*/
 #webId { position: relative; }
 .xuanfu {
  height: 54px; /* rem = 12px */
  width: 54px;
  /*1.3 如果碰到滑动问题，请检查 z-index。z-index需比web大一级*/
  z-index: 999;
  position: fixed;
  top: 4.2rem;
  right: 3.2rem;
  border-radius: 0.8rem;
  background-color: rgba(0, 0, 0, 0.55);
 }
 .yuanqiu {
  height: 2.7rem;
  width: 2.7rem;
  border: 0.3rem solid rgba(140, 136, 136, 0.5);
  margin: 0.65rem auto;
  color: #000000;
  font-size: 1.6rem;
  line-height: 2.7rem;
  text-align: center;
  border-radius: 100%;
  background-color: #ffffff;
 }
</style>