Working with Days

You might want to display a different message to your users if it's a weekend . Script 13.2 tells you how to do it.

Script 13.2. This script figures out if it is a weekday or weekend.

 window.onload = initDate; function initDate() {  var now = new Date();  var dtString;  if (now.getDay() > 0 && now.getDay() < 6) {   dtString = "Sorry, it's a weekday.";  }  else {   dtString = "Hooray, it's a weekend!";  }  document.getElementById("dtField"). innerHTML = dtString;  } 

To figure out if it is a weekend:

1.	var now = new Date(); Fill the variable now with the current date.
2.	if (now.getDay() > 0 && now. getDay() < 6) { This extracts the numerical day of the week from the now variable and asks if it is greater than 0 (remember that Sunday is 0). Next the line uses the && operator, which is a logical and (i.e., both parts have to be true), and asks if now is less than 6, which is the number for Saturday.
3.	dtString = "Sorry, it's a weekday."; If the result of the last expression is greater than 0 and less than 6, it has to be between 1 and 5, which is to say, from Monday to Friday, so the script puts a string to that effect into dtString .
4.	else { dtString = "Hooray, it's a weekend!"; If we failed the test in the step 2, it must be a weekend, and we put a string with the happy news in dtString .
5.	document.getElementById("dtField"). innerHTML = dtString; Finally, we set the innerHTML property of dtField to the value of dtString , just as in the previous example. The result is shown in Figure 13.2 .

Figure 13.2. The sad news gets written to the window.