Hiding JS code from old browsers

JavaScript FAQ | Basic Syntax & General Questions  

Question: How do I hide JS code from old browsers that do not support JavaScript?

Answer: This question has become far less relevant now that virtually all browsers support JavaScript. Nevertheless, to prevent old browsers from displaying your JS code, you can do the following:

  1. Immediately after the opening <script> tag, put a one-line HTML-style comment without the closing characters, so that the first two lines of your script would look like this: 
    <script type="text/javascript" language="JavaScript">
<!--
  2. At the end of your script, put the following two lines: 
    //-->
</script>
Thus, your HTML file will contain the following fragment: 
<script language="JavaScript">
<!--
Here you put your JS code.
Old browsers will treat it
as an HTML comment.
//-->
</script>

Old browsers will treat your JS code as one long HTML comment. On the other hand, new JavaScript-aware browsers will normally interpret JS code between the tags <script> and </script> (the first and last lines of your JS code will be treated by the JavaScript interpreter as one-line comments).

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