highCharts提示框中显示当前时间的方法

shared: true,//当提示框被共享时，整个绘图区都将捕捉鼠标指针的移动。提示框文本显示有序数据（不包括饼图，散点图和标志图等）的系列类型将被显示在同一个提示框中。
    formatter : function() {//提示框内容格式化回调函数，返回 false 可以针对某个点或数据列关闭提示框，该函数里可以执行复杂的逻辑来返回需要的内容。
      var content = '';
      for (var i = 0; i < this.points.length; i++) {
        if(i == this.points.length-1){
          content += '<span style="font-size: 10px; color: ' + this.points[i].series.color + '">' + this.points[i].series.name + '</span>: ' + this.points[i].y +'℃'+'<br/>';
        }else{
          content += '<span style="font-size: 10px; color: ' + this.points[i].series.color + '">' + this.points[i].series.name + '</span>: ' + this.points[i].y +'%'+'<br/>';
        }
      };
      var date = new Date();
      var nowYear=date.getFullYear().toString();
      var nowMonth=(date.getMonth() + 1).toString();
      var nowDay=date.getDate().toString(); 
      var nowHours=date.getHours().toString(); 
      var nowMin=date.getMinutes().toString(); 
      var nowSeconds=date.getSeconds().toString(); 
      function timeAdd0(str) { 
        if(str.length<=1){ 
          str='0'+str; 
        } 
        return str 
      } 
      nowYear=timeAdd0(nowYear) ;
      nowMonth=timeAdd0(nowMonth) ;
      nowDay=timeAdd0(nowDay) ;
      nowHours=timeAdd0(nowHours) ;
      nowMin=timeAdd0(nowMin);
      nowSeconds=timeAdd0(nowSeconds)
      content = '<span>' + nowYear + '/' + nowMonth + '/' + nowDay + ' ' + nowHours + ':' + nowMin + ':' + nowSeconds + ' year' + '</span><br/>' +content;
      return content;
    },