CS 101 - Lab 5

Due at end of lab during sixth week

JavaScript

<script> </script> - attributes: language

This tag is used to separate the JavaScript code from the remainder of the HTML code. The language attribute should have the value of "JavaScript". Also in case the browser viewing the page does not recognize the JavaScript code, all of the code should be enclosed in an HTML comment. The following example shows this done.

<script language="JavaScript">
<!-- This is the HTML Comment that hides the JavaScript code from old browsers

JavaScript code goes here

The JavaScript code can add dynamic information to a web page that static HTML code cannot. The use of the JavaScript statement document.write() is very useful for this.

The document object in JavaScript allows a number of useful methods and properties. Check out chapter 16 in the text for a discussion of more items than covered here. We will

• document.write()

  The document.write() method allows text information (strings) to be added to the the HTML code. The parameter of the method (the stuff placed between the parentheses) can be a single string or a multiple strings separated by commas. Whatever is written will then be interpreted by the web browser as HTML code, so you can include HTML tags to help format the information being written.

• document.URL

  The document.URL property gives the URL of the current page.

• document.lastModified

  The document.lastModified property gives the date and time that the web page was last modified. Note this property gives the information as a Date object. See chapter 28 of the text for addition information about the Date object.

The Date object allows JavaScript code to retrieve specific information about the dat stored in the Date object.

• new Date()

  This will create a new Date object with the current date and time.

• getMonth() - get month of year (January = 0)
• getDate() - get date within the month (1 - 31)
• getYear() - get year (0 = 1900)
• getDay() - get day of week (Sunday = 0)
• getHours() - get hour of day in 24 hour time
• getMinutes() - get minute of hour
• getSeconds() - get second of minute

  The above methods will return the specified data when used with a Date object that alread has a date stored in it.

Lab Assignment

1. your name
2. day and time of your CS 101 lab section (i.e. Wendesday at 9:00)
3. the URL of the web page (using the document.URL property)
4. the month, day and year when the web page was last modified (using the document.lastModified property)
5. the "current" time in hours and minutes. By "current" time, list the time when the page was load. You do not have to keep updating the time value as every minute passes.