code: function TimeInterval(startHour, startMin, endHour, endMin){
  
  	this.start = {
  		hour: null,
  		min: null
  	};
  	this.end = {
  		hour: null,
  		min: null
  	};
  
  	//效验时间合法性
  	if(parseInt(startHour) !== startHour || startHour < 0 || startHour > 23 || 
  		parseInt(startMin) !== startMin || startMin < 0 || startMin > 59 || 
  		parseInt(endHour) !== endHour || endHour < 0 || endHour > 23 || 
  		parseInt(endMin) !== endMin || endMin < 0 || endMin > 59){
  
  		throw new Error('startHour or startMin or endHour or endMin is invalid');
  	}
  
  	this.start.hour = startHour + '';
  	this.start.min  = startMin + '';
  	this.end.hour   = endHour + '';
  	this.end.min    = endMin + '';
  
  }
docs: 表示一个允许推送的时间闭区间，从startHour：startMin到endHour：endMin
  @param {int} startHour 开始小时
  @param {int} startMin  开始分钟
  @param {int} endHour   结束小时
  @param {int} endMin    结束分钟