In this tutorial we show how to generate random numbers using JavaScript, and include some useful and entertaining tricks that you can do with random numbers.

We can use JavaScript to generate random numbers, that is, numbers that are different each time the script is run. This allows us to do all sorts of fun stuff, such as:

Arrays really come in to their own when you access their index numbers. You can use a variable in place of the index number. Then, if you increment the variable, you can access the elements in your array. As an example, try this script in a web page. For the web page, create a form called frmOne. Put a button on the form, and a text box called txtSeason. If you prefer, copy and paste this one:

Drawing Board: Using a table and different event handlers to change the background of the Cells of the table. It is really Simple Code

The Math object of JavaScript allows you to perform certain calculations by using method functions of the Math object. Also, it provides a few constants such as pi. The easiest way to get a value is to define a variable and set its value to a property or function of the Math Object.

If you want to use a property, which returns a constant value (such as pi), you would write something like this:

var my_car=Math.property;

You would replace the word "property" with the property you want to use. So, if you want to use the value of pi in a variable, you would use the PI property of the Math object. You would write:

Validating user input is the bane of every software developer’s existence. When you are developing cross-browser web applications (IE4+ and NS4+) this task becomes even less enjoyable due to the lack of useful intrinsic validation functions in JavaScript. Fortunately, JavaScript 1.2+ has incorporated regular expressions. In this article I will present a brief tutorial on the basics of regular expressions and then give some examples of how they can be used to simplify data validation.