What is the best practice to include CSS and Scripts in php? [duplicate]


I’ve read this: PHP & CSS – Should I Link or Include?
and this: What is the best practice to include header and footer in PHP?
and also this: Creating a PHP header/footer

Nice pieces of information there, but my question is different.
I am including header and footer no problem. Sometimes I face this issue:

Different pages with different data and different scripts required, specifically Ajax. I separate my Ajax post requests with different files to include it only on its page. Of course if I have all the <link> and <script> in header.php and footer.php they will be included everywhere, so thats useless code being rendered.

Someone in Stackoverflow once told me that it’s not a good practice to write an if condition to run scripts based on a page.

So what is the best practices for this?


Kindly don’t be harsh on me if this question might be so simple, being a self taught developer makes me miss lots of "might be basic" things since I don’t have a person to guide me. Appreciate it.

Source: Ask PHP