JavaScript中防止微信浏览器被整体拖动的方法

html
  head
    title 微信拖动测试
    meta(charset="utf-8")
    meta(name="viewport", content="initial-scale=1, maximum-scale=1, minimum-scale=1")
    link(rel='stylesheet', href='/stylesheets/style.css')
    script(src="http://apps.bdimg.com/libs/zepto/1.1.4/zepto.min.js")
  body
    #container
      .header
        | header
      .page
        .box box1 in page
        .box box2 in page
        .box box3 in page
        .box.bottom box4 in page
  script.
    $(function() {
      var startY, endY;
      var box_height = $('#container').height();
      $('.page').on('touchstart', function(event) {
        event.stopPropagation();
        startY = event.touches[0].pageY;
      });
      $('.page').on('touchmove', function(event) {
        event.stopPropagation();
        var endY = event.changedTouches[0].pageY;
        var changedY = endY - startY;
        var scroll_top = $('.page').scrollTop();
　　　　　　　　　 // 判断是否在顶部，且向下拖动
        if (scroll_top === 0 && changedY > 0) {
          event.preventDefault();
        }
　　　　　　　　　 // 判断是否在底部，且向上拖动
        var o = $('.bottom').offset();
        if (o.top + o.height === box_height && changedY < 0) {
          event.preventDefault();
        }
      });
　　　　　　　// header禁止拖动
      $('.header').on('touchmove', function(event) {
        event.preventDefault();
      });
    });

*{
  padding: 0;
  margin: 0;
}
#container{
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  background-color: #efefef;
  color: #fff;
  text-align: center;
  font-size: 40px;
}
.header{
  position: absolute;
  left: 0;
  right: 0;
  height: 80px;
  line-height: 80px;
  background-color: #ddd;
}
.page{
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  top: 80px;
  background-color: #ccc;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}
.page > *{
  z-index: 1;
}
.box{
  width: 100%;
  height: 300px;
  line-height: 300px;
  box-sizing: border-box;
  border-bottom: 2px solid #fff;
}