What Else Can You Do With The Date? - Page 7

In the night and day script, we worked with the time in hours. Of course, JavaScript lets you access all parts of the date and time, but the syntax isn't exactly plain English. Table 1-2 shows how to get the various parts of the date and the form in which they're returned.

Unit of time	How to get it	How to use it
Second	second = now.getSeconds( );	The time in seconds is returned as a number 0 through 59.
Minute	minute = now.getMinutes( );	The time in minutes is returned as a number 0 through 59.
Hour	hour = now.getHours( );	The time in hours is returned as a number 0 (midnight) through 23 (11 P.M.).
Day	day = now.getDay( );	The day of the week is returned as a number 0 (Sunday) through 6 (Saturday).
Month	month = now.getMonth( );	The month of the year is returned as a number 0 (January) through 11 (December).
Year	year = now.getFullYear( );	The year as a full four digit year (e.g., 1998, 2001).

Keep in mind that when you get times and dates from JavaScript, they are returned as numbers, not words. This means that if you ask a Date object for the day of the week, using getDay( ), you get a number 0 through 6, not the name of a day, like Sunday or Monday. Though numbers are useful for database applications and the like, you may want to put them into a more digestible form. For example, you can create a script that uses getDay( ) in combination with if statements to translate the numeric values to their actual names, as shown in Example 1-4.

Example 1-4: Connecting number values to day names

<script language="JavaScript">
var now = new Date(  );
var day = now.getDay(  );
var dayname;
if (day == 0) { 
    dayname = "Sunday";
}
if (day == 1) {
    dayname = "Monday";
}
if (day == 2) {
    dayname = "Tuesday";
}
if (day == 3) {
    dayname = "Wednesday";
}
if (day == 4) {
    dayname = "Thursday";
}
if (day == 5) {
    dayname = "Friday";
}
if (day == 6) {
    dayname = "Saturday";
}
document.write("Today is " + dayname + ". <br>");
</script>

So how does this work? First, a new Date object named now is created, and the day of the week, which is in number form, is given to a variable named day. Then a series of if statements matches up the number of the day with the day's full name and stores the name in the variable dayname. For example, if day is 0, it must be Sunday; if day is 1, it must be Monday, etc. Finally, the day's full name, in variable dayname, is displayed on the page using document.write( ). Note that this script creates the variable dayname without giving it a value at the same time; the value is assigned later when we actually figure out what day it is.

You can use this technique for various parts of the date to create a script that displays the fully formatted date on the page (e.g., Monday, July 30, 2001). The best way to do this involves arrays, something you'll learn more about later in this book. If you're curious, see "Doing the date right," in Chapter 5.

Document Properties - Page 6
Designing with JavaScript, 2nd Edition
Objects, Properties, And Methods - Page 8