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PHP include and require statements
In PHP, you can insert the contents of a file into the PHP file before it is executed by the server .
include and require statements are used to insert useful code written in other files into the execution flow.
In addition to the different ways of handling errors, include and require are the same in other aspects: (Recommended learning: PHP programming from entry to proficiency)
require generates a fatal error (E_COMPILE_ERROR), after which the script will stop executing.
include generates a warning (E_WARNING) and the script will continue execution after the error occurs.
So if you want to continue execution and output results to the user even if the included file is missing, then use include. Otherwise, in frameworks, CMS, or complex PHP application programming, always use require to reference key files to the execution flow. This helps improve application security and integrity in the event that a critical file is accidentally lost.
Including files saves a lot of work. This means you can create standard header, footer or menu files for all web pages. Then, when the header needs updating, you simply update the header include file.
Syntax
include 'filename';或者require 'filename';
PHP include and require statements
Basic examples
Suppose you have a standard header file named "header.php". To reference this header file in the page, please use include/require:
<html> <head> <meta charset="utf-8"> </head> <body> <?php include 'header.php'; ?> <h1>欢迎来到我的主页!</h1> <p>一些文本。</p> </body> </html>
Example 2
Suppose we have a standard menu that is used in all pages document.
"menu.php": echo '<a href="/">主页</a> <a href="/html">HTML 教程</a> <a href="/php">PHP 教程</a>';
All pages in the website should reference this menu file. The following is the specific approach:
<html> <head> <meta charset="utf-8"> </head> <body> <div class="leftmenu"> <?php include 'menu.php'; ?></div> <h1>欢迎来到我的主页!</h1> <p>一些文本。</p> </body> </html>
Example 3
Assume we have an include file ("vars.php") that defines variables:
<?php $color='red';$car='BMW';?>
These variables can be used in the calling file:
<html> <head> <meta charset="utf-8"> </head> <body> <h1>欢迎来到我的主页!</h1> <?php include 'vars.php';echo "I have a $color $car"; // I have a red BMW ?></body> </html>
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