HTML COMPONENTS Part 4

===Writing Calendar 1===

　When calendar.html is called MYCAL:CALENDAR, the current month's calendar will be displayed on the page. The function setCal() is the main program segment. It initializes some variables and calls the drawCal() function. We also use three other functions: getMonthName(), getDays() and leapYear(). Let's start with the last function:

　The getDays() function receives which month value and which year value, and creates an array with 12 elements to store the number of days in each month, and which year is used to determine whether it is a leap year. , February has 29 days in a leap year, instead of 28 days in a leap year. This function returns the number of days in the specified month.

The following is 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); 
}

The above is the content of the fourth HTML component (HTML COMPONENTS). For more related articles, please pay attention to the PHP Chinese website (www.php.cn)!