将外部jQuery和CSS文件嵌入到index.php文件中

I have a specific question. How do I embed external .js or .css file in a php file extension?

It does not work the way I embed it in html file extension.

You would usually include these inside the <head> tags

<link rel="stylesheet" type="text/css" href="myStyles.css">
<script src="myScript.js"></script>

But if you must use php for whatever reason, you can use

<? include "myScript.php"; ?>

EDIT:

In response to your comment about targeting outputted text, you would simply echo the text between an identifiable tag. Eg:

<span id:="targetThis">
    <? echo "Text" ?>
</span>

Now you can target the text in Css using:

#targetThis {
    color: red;
}

You can also grab it using JQuery using:

$('#targetThis') then do whatever it is you wanted to do with it...

$('#targetThis').html('Edited Text');