Comments in JavaScript

JavaScript FAQ | Basic Syntax & General Questions  

Question: How do I insert comments in JavaScript code?

Answer: JavaScript supports three different types of comments:

  1. Multiple-line C-style comments. Everything between
    is a comment, for example:
    /* This is a comment */
    /* C-style comments can span
    as many lines as you like,
    as shown in this example */
  2. One-line comments of C++ style. These comments begin with
    and continue up to the next line break:
    // This is a one-line comment
  3. One-line comments with the HTML comment-opening sequence (
    ). Note that the JavaScript interpreter ignores the closing characters of HTML comments (
    ). Consider this example:
    <!-- This is treated as a one-line JS comment
    <!-- It works just like a comment beginning with //
    <!-- --> This is also a one-line JS comment
    <!-- --> because JS ignores the closing characters
    <!-- --> of HTML-style comments
    HTML-style comments are not usually found in the middle of JavaScript code. (The
    comments are simpler and easier to read.) However, they are useful for hiding JavaScript code from old browsers.

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