当calendar.html调用 MYCAL:CALENDAR,当月的日历将会显示在页面中，函数setCal()是主要程序段，它初始化一些变量并调用drawCal()函数。我们也使用了三个别的函数：getMonthName()、 getDays() 和 leapYear()。让我们从最后一个函数开始：

　　getDays()函数接收哪月值和哪年值，并且建立一个有12个元素的数组，用来存放每月的天数，哪一年用来决定是不是闰年，在闰年中二月是29天，而不是闰年是28天。该函数返回指定月份的天数。

以下是getDays()：

function getDays(month, year) { 
// create array to hold number of days in 
each month 
var ar = new Array(12); 
ar[0] = 31; // January 
ar[1] = 
(leapYear(year)) ? 29 : 28; // February 
ar[2] = 31; // March 
ar[3] = 30; 
// APRil 
ar[4] = 31; // May 
ar[5] = 
30; // June 
ar[6] = 31; // July 
ar[7] = 31; // August 
ar[8] = 30; // 
September 
ar[9] = 31; // October 
ar[10] = 30; // November 
ar[11] = 
31; // December 

// return number of days in the specified month 
(parameter) 
return ar[month]; 
} 
如果指定的年数可以被4整除，那么leapYear()函数将返回“true”，否则返回”false“： 
function leapYear(year) { 
if (year % 4 == 
0) // basic rule 
return true; // is leap year 
/* else */ // else not 
needed when statement is "return" 
return false; // is not leap year 
} 
getMonthName()函数返回指定月份的名字： 
function getMonthName(month) { 
// create 
array to hold name of each month 
var ar = new Array(12); 
ar[0] = 
"January"; 
ar[1] = "February"; 
ar[2] = "March"; 
ar[3] = "April"; 
ar[4] = "May"; 
ar[5] = "June"; 
ar[6] = "July"; 
ar[7] = "August"; 
ar[8] = "September"; 
ar[9] = "October"; 
ar[10] = "November"; 
ar[11] = "December"; 

// return name of specified month (parameter) 
return ar[month]; 
} 
setCal()函数是主模块，我们在脚本的第一行调用它。该函数为当天（now）、和每月的第一天（firstDayInstance）建立一个Date对象。用这些对象，setCal()函数解析出关于一个月的第一天、当日，和最后一天的所有信息。 
function setCal() { 
// standard time 
attributes 
var now = new Date(); 
var year = now.getFullYear(); 
var 
month = now.getMonth(); 
var monthName = getMonthName(month); 
var date = 
now.getDate(); 
now = null; 

// create instance of first day of month, 
and extract the day on which it occurs 
var firstDayInstance = new Date(year, 
month, 1); 
var firstDay = firstDayInstance.getDay(); 
firstDayInstance = 
null; 

// number of days in current month 
var days = getDays(month, 
year); 

// call function to draw calendar 
drawCal(firstDay + 1, days, 
date, monthName, year); 
}