时间对象的格式化

format_datetime.js

Date.prototype.format = function (format) {
  /*     
   * eg:format="YYYY-MM-dd hh:mm:ss";  
   */       
  var o = { 
    "M+" : this.getMonth() + 1, // month
    "d+" : this.getDate(),      // day
    "h+" : this.getHours(),     // hour
    "m+" : this.getMinutes(),   // minute
    "s+" : this.getSeconds(),   // second
    "q+" : Math.floor((this .getMonth() + 3) / 3),  // quarter
    "S"  : this.getMilliseconds()
    // millisecond
  }         
            
  if (/(y+)/.test(format)) {
    format = format.replace(RegExp.$1, (this.getFullYear() + "") 
            .substr(4 - RegExp.$1.length));
  }         
            
  for (var k in o) {
    if (new RegExp("(" + k + ")").test(format)) {
      format = format.replace(RegExp.$1, RegExp.$1.length == 1 ? o[k]
              : ("00" + o[k]).substr(("" + o[k]).length));
    }       
  }         
  return format;                                                                                                                                                                              
}

测试
nowDate =  new  Date().format( "yyyy-MM-dd" );