JAVASCRIPT

An in depth discussion of JavaScript Arrays

This series of articles mainly concentrates on working with JavaScript arrays. We shall start with the basics of JavaScript arrays and finally conclude with complex object based arrays in JavaScript. You can reuse these scripts to inject into server side controls easily (especially in .NET and Java).

Author Info:

By: Jagadish Chaterjee

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February 28, 2006

TABLE OF CONTENTS:

<html>
      <head>
            <meta name=vs_targetSchema
content="http://schemas.microsoft.com/intellisense/ie5">
<script id="clientEventHandlersJS" language="javascript">

            </script>
      </head>
      <body>
      <form id="form1">
                  <input type="button" value="Show" id="Button1"
name="Button1" onclick="return Button1_onclick()">
            </form>
      </body>
</html>

Let us work on understanding the above a bit. Consider the following code fragment.

      var salaryArray = [[2300, 3105, 2909, 4800],
                  [1800, 1940, 2470, 4350],
                  [900, 1200, 1923, 3810]];

The above declaration directly creates a two dimensional array named “salaryArray.” This is a straightforward process if you know all the values directly. If you don’t know the values immediately at the time of declaration, the method discussed in the previous sections may be suitable. Even though the declarations are different, the working model is the same in both cases.

The most important issue to remember when using the above method is that the values must be grouped within a set of square brackets for every row of information. Finally, you will combine all of those arrays in another set of square brackets. If you are confused, I suggest you implement the following method:

      var salaryArray =
            [
                  [2300, 3105, 2909, 4800],
                  [1800, 1940, 2470, 4350],
                  [900, 1200, 1923, 3810]
            ];

The above looks pretty and more understandable than the one before it. Let us consider the following declaration:

      var salaryArray =
            [
                  2300, 3105, 2909, 4800,
                  1800, 1940, 2470, 4350,
                  900, 1200, 1923, 3810
            ];

Even though the above declaration is similar to the previous one (I eliminated the internal sets of square brackets), this would be treated as a single dimensional array, which is quite dangerous!

Any comments, suggestions, ideas, improvements, bugs, errors, feedback etc. are highly appreciated at jag_chat@yahoo.com.

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