var d=new Date()
function Calendar(name){
  document.write('<div id="calendar"></div>');
  this.name = name;
  this.now = new Date();
  this.year = this.now.getFullYear();
  this.month = this.now.getMonth();
  this.day = this.now.getDate();
  this.monthName = new Array('January','February','March','April','May','June','July','August','September','October','November','December');
  this.weekName = new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday');
  this.daysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31,30, 31, 30, 31);
  this.element = document.getElementById('calendar');
  this.init();
}
Calendar.prototype.init = function() {
  var strHtml = '';
  strHtml += this.createHead();
  strHtml += this.createWeek();
  strHtml += this.createDays();
  strHtml += this.createFoot();
  this.element.innerHTML = strHtml;
}
Calendar.prototype.getDays = function() {
  if (1 == this.month) return ((0 == this.year % 4) && (0 != (this.year % 100))) ||(0 == this.year % 400) ? 29 : 28;
  else return this.daysInMonth[this.month];
}
Calendar.prototype.createHead = function() {
  return '<span class="head">' + this.monthName[this.month] + ' ' + this.year + '</span>';
}
Calendar.prototype.createWeek = function() {
  var strResult = '';
  for (var i = 0; i < 7; i++) {
    if (i == 0 || i == 6) strResult += '<span class="we">';
    else strResult += '<span class="ww">';
    strResult += this.weekName[i].substr(0,2) + '</span>';
  }
  return strResult;
}
Calendar.prototype.createDays = function() {
  var strResult = '';
  var i = 0;
  var d = this.getDays();
  var n = Math.ceil(d / 7) * 7;
  var w = new Date(this.year, this.month, 1).getDay();
  for (var j = 0; j < w; j++) { //输出前空格
    i += 1;
    strResult += '<span>&nbsp;</span>';
  }
  for (var j = 1; j <= d; j++) { //输出日期格
    i += 1;
    if (j == this.day ) {
      strResult += '<span>' + j + '</span>'; //delete class="today" by Ri.
    } else {
      var k = new Date(this.year, this.month, j).getDay();
      if (k == 0 || k == 6) {
        strResult += '<span class="weekend">' + j + '</span>';
      } else {
        strResult += '<span>' + j + '</span>';
      }
    }
  }
  for (var j = 0; j < (Math.ceil(i / 7) * 7 - i); j++) { //输出后空格
    strResult += '<span>&nbsp;</span>';
  }
  return strResult;
}
Calendar.prototype.createFoot = function() {
  return '<span class="foot"><a href="javascript:' + this.name + '.changeMonth(\'p\');" class="arrow">3</a> MONTH <a href="javascript:' + this.name + '.changeMonth(\'n\');" class="arrow">4</a>　　<a href="javascript:' + this.name + '.changeYear(\'p\');" class="arrow">3</a> YEAR <a href="javascript:' + this.name + '.changeYear(\'n\');" class="arrow">4</a></span>';
}
Calendar.prototype.changeYear = function(arg) {
  if (arg == 'p') this.year -= 1;
  if (arg == 'n') this.year += 1;
  this.init();
}
Calendar.prototype.changeMonth = function(arg) {
  var m;
  if (arg == 'p') m = this.month - 1;
  if (arg == 'n') m = this.month + 1;
  if (arg == 'p' || arg == 'n') {
    if ( m > -1 && m < 12) {
      this.month = m;
    } else if (m < 0) {
      this.year -= 1;
      this.month = 11;
    } else if (m > 11) {
      this.year += 1;
      this.month = 0;
    }
  }
  this.init();
}