위챗 애플릿은 현재 위치와 목적지의 거리를 제한합니다(출석체크)

  onLoad: function (options) {
    var that = this;
    campaign_id = campaign_id
    wx.getLocation({
      type: 'wgs84',
      success: function (res) {
        console.log(res)
        lat1 = res.latitude,
          lng1 = res.longitude
      }
    })
  }

  site: function () {
    var that = this;
    wx.chooseLocation({
      success: function (res) {
        // name	 
        // address	 
        // latitude	 ， ，  - 90~90， 
        // longitude	 ， ，  - 180~180， 
        console.log(res);
        var site_val = res.address;
        lat2 = res.latitude;
        lng2 = res.longitude;
        if (Number(juli(lat1, lng1, lat2, lng2))>0.5){
          wx.showModal({
            title: ' ',
            content: ' 500 ',
            success: function (res) {
              if (res.confirm) {
                  that.site()
              } else if (res.cancel) {
                console.log(' ')
              }
            }
          });
        }else{
          that.setData({
            site_val: site_val
          });
        }
        console.log(' km：',juli(lat1, lng1, lat2, lng2));
      }
    })
  },

//  
function juli(lat1, lng1, lat2, lng2) {
  console.log(lat1, lng1, lat2, lng2)
  var radLat1 = lat1 * Math.PI / 180.0;
  var radLat2 = lat2 * Math.PI / 180.0;
  var a = radLat1 - radLat2;
  var b = lng1 * Math.PI / 180.0 - lng2 * Math.PI / 180.0;
  var s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
  s = s * 6378.137;
  s = Math.round(s * 10000) / 10000;
  return s
}