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How to Put a JavaScript Into an HTML Page

How to Put a JavaScript Into an HTML Page

<html>
<body>
<script type="text/javascript">
document.write("Hello World!");
</script>
</body>
</html>

The code above will produce this output on an HTML page:

Hello World!

Example Explained

To insert a JavaScript into an HTML page, we use the <script> tag. Inside the <script> tag we use the type attribute to define the scripting language.
So, the <script type="text/javascript"> and </script> tells where the JavaScript starts and ends:

<html>
<body>
<script type="text/javascript">
...
</script>
</body>
</html>

The word document.write is a standard JavaScript command for writing output to a page.
By entering the document.write command between the <script> and </script> tags, the browser will recognize it as a JavaScript command and execute the code line. In this case the browser will write Hello World! to the page:

<html>
<body>
<script type="text/javascript">
document.write("Hello World!");
</script>
</body>
</html>

Note: If we had not entered the <script> tag, the browser would have treated the document.write("Hello World!") command as pure text, and just write the entire line on the page.


HTML Comments to Handle Simple Browsers

Browsers that do not support JavaScript will display JavaScript as page content.
To prevent them from doing this, and as a part of the JavaScript standard, the HTML comment tag can be used to "hide" the JavaScript. Just add an HTML comment tag <!-- before the first JavaScript statement, and a --> (end of comment) after the last JavaScript statement.

<html>
<body>
<script type="text/javascript">
<!--
document.write("Hello World!");
//-->
</script>
</body>
</html>

The two forward slashes at the end of comment line (//) is the JavaScript comment symbol. This prevents JavaScript from executing the --> tag.
How to Put a JavaScript Into an HTML Page Reviewed by 1000sourcecodes on 07:48 Rating: 5
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