noscript

The noscript element represents nothing if scripting is enabled, and represents its children if scripting is disabled. It is used to present different markup to user agents that support scripting and those that don't support scripting, by affecting how the document is parsed.

<script>
 /* Do stuff with JavaScript */
</script>
<noscript>
For full functionality of this site it is necessary to enable JavaScript. Here are the <a href="https://www.enable-javascript.com/" >instructions how to enable JavaScript in your web browser</a>.
</noscript>
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