It’s always a good practice to add jQuery code in footer i.e. just before the closing </body> tag. If you have not done that, then use the defer attribute.
Use defer attribute so the web browser knows to download your scripts after the HTML downloaded −
<script src="new.js" defer="defer"></script>
The defer attribute is used to specify that the script execution occurs when the page loads. It is useful only for external scripts and is a boolean attribute.
The following code shows how to use the defer attribute −
<!DOCTYPE html> <html> <body> <script src="new.js" defer></script> <p>The external file added will load later, since we're using defer</p> </body> </html>