Simple JavaScript Programs

*************Basic Structure of a Javascript/Html program**********

Every Javascript program takes the basic structure below, where we set all the html tags. Notice that the script tag is placed inside the body of the html (this can also be placed in the head). Also notice the other html elements in the body part of the program, those are the elements that are displayed on the web page.

<!DOCTYPE html>

<html>

<head>

<title> INTRODUCTION TO JAVASCRIPT</title>

</head>

<body>

<img id="source_image" alt=".." />Original Image

</body>

</html>

----Basic structure of html components

To create your first code:

----Open you desired text editor (Notepad++ in our example)

-----Add all HTML tags and elements.

-----Add a script tag to the HTML head or body.

To do so, insert a <script language="javascript"> tag in the head or in the body.

This tells the text editor that you'd like to use JavaScript language to write your HTML JavaScript "program.“

Add the script tag: If you want the script to run automatically run when the site loads, don't include a function. If you want to call your script (maybe using a button or label), then include a function.

-----•Call up Another JavaScript scripts using a JavaScript function.

You can also call another script If you know where the script file can be found, add a src= property to the script tag and include the complete web address or file path for the JavaScript file.

•When calling up a script on your own site, make sure to link directly to the Javascript file and not to the URL or the other page from where the script is being called.

-----Save the html file (using any file name with .html extension)

-----Run it by double clicking on the file name at the file location