Example 2
Now, let's assume we have a standard menu file that should be used on all pages (include files usually have a ".php" extension). Look at the "menu.php" file below:
Home |
About Us |
Contact Us
The three files, "default.php", "about.php", and "contact.php" should all include the "menu.php" file. Here is the code in "default.php":
Welcome to my home page
Some text
If you look at the source code of the "default.php" in a browser, it will look something like this:
Home |
About Us |
Contact Us
Welcome to my home page
Some text
And, of course, we would have to do the same thing for "about.php" and "contact.php". By using include files, you simply have to update the text in the "menu.php" file if you decide to rename or change the order of the links or add another web page to the site.
The require() Function
The require() function is identical to include(), except that it handles errors differently.
The include() function generates a warning (but the script will continue execution) while the require() function generates a fatal error (and the script execution will stop after the error).
If you include a file with the include() function and an error occurs, you might get an error message like the one below.
PHP code:
include("wrongFile.php");
echo "Hello World!";
?>
Error message:
Warning: include(wrongFile.php) [function.include]:
failed to open stream:
No such file or directory in C:\home\website\test.php on line 5
Warning: include() [function.include]:
Failed opening 'wrongFile.php' for inclusion
(include_path='.;C:\php5\pear')
in C:\home\website\test.php on line 5 Hello World!
Notice that the echo statement is still executed! This is because a Warning does not stop the script execution.
Now, let's run the same example with the require() function.
PHP code:
require("wrongFile.php");
echo "Hello World!";
?>
Error message:
Warning: require(wrongFile.php) [function.require]:
failed to open stream:
No such file or directory in C:\home\website\test.php on line 5
Fatal error: require() [function.require]:
Failed opening required 'wrongFile.php'
(include_path='.;C:\php5\pear')
in C:\home\website\test.php on line 5
The echo statement was not executed because the script execution stopped after the fatal error.
It is recommended to use the require() function instead of include(), because scripts should not continue executing if files are missing or misnamed.