When a browser doesn’t support Javascript or has it disabled, it’s best to include an alternative non-Javascript content for the page to remain functional.

It is made possible with the noscript tag, and the example below will pop up the alert if Javascript is enabled or supported and display the text instead if it doesn’t. 

<script type="text/javascript">     window.alert("I support Javascript") </script> <noscript>     I do not support Javascript </noscript>