PHP：@include_once用于动态加载的内容？

Question

I have this header.php which I included in all the pages I need it. I used @include_once('header.php'); in order to be able to load the page via AJAX into the "container" div of another page without having to worry about it being showed twice. But since both the main page and the loaded page have the header included, the header is showing twice. I thought include_once was supposed to not let that happen. What should I do?

Answer 1

Jon's recommendation is the "right way" -- re-architect your system so the header is included only when it's needed.

However, as an (computationally expensive) workaround, in your code that includes the header via AJAX, you can check for the existence of an element that only exists in header.php:

//We know that the string "<div id='header'> exists only in header.php
if( $('#header').length < 1 )
{
     //your including header.php code here
}