Bro thank you so much for the reply, but the issue at hand is take for instance a php website with multiple pages, were the header and footer is in different files using php include statement to include the header and footer i. e <?php include "header" ; ?>
And an external javascript file linked in the header or footer. I. e for instance <javascript src="mm.Js">
And a button located in the header page, since the header is included in all pages, that makes the one button appear in all pages, the button is to trigger a javascript function inside the linked javascript file for instance a function to alert "hello world ", now when the button is clicked on the index page it triggers the function but when the same button is clicked in the other pages the function Will not be triggered...

Hello guys I need assist on something in javascript, my code is working only in index page and not in all other pages..