<html>
    <head> 
       <script async src="https://www.googletagmanager.com/gtag/js?id=xxxxx">         
       </script>
<html>
        replace value xxx by var get from config 
<script async  src="https://www.googletagmanager.com/gtag/js?id=Var">
I want to replace the value of the id in src of script with a variable that I get from conf file
any help?
 
    