How can the plugin directory path be returned into ?

Take a look at this: https://wordpress.stackexchange.com/a/119084/121955

plugins_url( "path/to/file", __FILE__ );

EDITED:

<script src="https://wordpress.stackexchange.com/questions/320046/<?php echo plugins_url("path/to/file", __FILE__ ); ?>"></script>

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)