对一个按钮设置bindtap的事件，采集到的数据中，有一项是force，如下所示：

{"type":"tap","timeStamp":7667,"target":{"id":"","offsetLeft":0,"offsetTop":0,"dataset":{}},"currentTarget":{"id":"","offsetLeft":0,"offsetTop":0,"dataset":{}},"detail":{"x":276.4107360839844,"y":22.62050437927246},"touches":[{"identifier":0,"pageX":276.4107360839844,"pageY":22.62050437927246,"clientX":276.4107360839844,"clientY":22.62050437927246,"force":1}],"changedTouches":[{"identifier":0,"pageX":276.4107360839844,"pageY":22.62050437927246,"clientX":276.4107360839844,"clientY":22.62050437927246,"force":1}],"_requireActive":true,"_relatedInfo":{"anchorTargetText":"一键复制","anchorRelatedText":"","anchorTapTime":1549955498761}}

其中"force":1这个字段是什么含义？ 官网文档并无解释。特此求助。