Arrays

Javascript supports both ordinary and associative arrays. It has an Array object:

• Create an Array with the new method, e.g.:

  var items = new Array()

  or

  var items = new Array(20)

• Assign an element, e.g.:

  items[i] = value

• Apply various methods, including joining, reversing and sorting.

• the Not (!) logical operator
• the Not equal (!=) comparison operator
• the select() method of the Text object

Lab

• Here is a little web page that displays today's date numerically.
• Here is its source code.
• Modify it to show month names instead of numbers, e.g. "March" instead of "3".
• Hint: use an array of strings.
• Solution and source code. Don't peek unless you're stuck!
• Extra credit: Show the day of the week, too.
• Solution and source code.

Extra for Experts

• Copy the example from the top of the chapter and edit it as follows.
• Add a third field to elicit the year.
• Add logic to handle leap years.
• You will need the modulo (%) arithmetic operator
• Allow the user to enter the data into the fields in any order.
• Add a button for the user to click to check that the number of days is correct for that month in that year.
• Of course, only February's number of days varies from year to year.
• Solution:
  • Run it.
  • Source code.