JavaScript Comments

Posted by champtutorial On Monday, 5 September 2011 0 comments

JavaScript Comments

Comments can be added to explain the JavaScript, or to make the code more readable.

Single line comments start with //.

The following example uses single line comments to explain the code:

Example:

<script type="text/javascript">

// Write a heading

document.write("<h1>This is a heading</h1>");

// Write two paragraphs:

document.write("<p>This is a paragraph.</p>");

document.write("<p>This is another paragraph.</p>");

</script>

JavaScript Multi-Line Comments

Multi line comments start with /* and end with */.

The following example uses a multi line comment to explain the code:

Example:

<script type="text/javascript">

/*

The code below will write

one heading and two paragraphs

*/

document.write("<h1>This is a heading</h1>");

document.write("<p>This is a paragraph.</p>");

document.write("<p>This is another paragraph.</p>");

</script>

Using Comments to Prevent Execution

In the following example the comment is used to prevent the execution of a single code line (can be suitable for debugging):

Example:

<script type="text/javascript">

//document.write("<h1>This is a heading</h1>");

document.write("<p>This is a paragraph.</p>");

document.write("<p>This is another paragraph.</p>");

</script>

in the following example the comment is used to prevent the execution of a code block (can be suitable for debugging):

Example:

<script type="text/javascript">

/*

document.write("<h1>This is a heading</h1>");

document.write("<p>This is a paragraph.</p>");

document.write("<p>This is another paragraph.</p>");

*/

</script>

Using Comments at the End of a Line

In the following example the comment is placed at the end of a code line:

Example:

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