The hyper-global variables introduced in PHP 4.1.0 are built-in variables that are always available in all scopes.
PHP Global Variables-Super global variables
Many of the predefined variables in PHP are "hyper-global", which means they are available in all scopes of a script. There is no need to perform a global $variable in a function or method; You can access them.
These hyper-global variables are:
$GLOBALS$_SERVER$_REQUEST$_POST$_GET$_FILES$_ENV$_COOKIE$_SESSION
$GLOBALS-Referencing all variables available in the global scope
$GLOBALS This global variable is used anywhere in the PHP script to access global variables (from functions or methods).
PHP stores all global variables in an array named $GLOBALS [index]. The name of the variable is the key of the array.
The following example shows how to use the Super global variable $GLOBALS:
Instance
$x = 75; $y = 25;functionaddition() {$GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y']; }addition(); echo$z; ?>
PHP $_server
$_server This hyper-global variable holds information about the header, path, and location of the script.
The following example shows how to use some of the elements in $_server:
Instance
echo$_SERVER['PHP_SELF'];echo"
";echo$_SERVER['SERVER_NAME'];echo"
";echo$_SERVER['HTTP_HOST'];echo"
";echo$_SERVER['HTTP_REFERER'];echo"
";echo$_SERVER['HTTP_USER_AGENT'];echo"
";echo$_SERVER['SCRIPT_NAME'];?>
The following table lists the most important elements that you can access in $_server:
PHP $_request
PHP $_request is used to collect data submitted by HTML forms.
$_REQUEST 来收集 input 字段的值:
Instance
<html><body><formmethod="post"action="
"><inputtype="text"name="fname"><inputtype="submit">
form>
$name = $_REQUEST['fname']; echo$name; ?>
body>
html>
PHP $_post
method="post" 的 HTML 表单后的表单数据。$_POST 也常用于传递变量。下面的例子展示了一个包含输入字段和提交按钮的表单。当用户点击提交按钮来提交数据后,表单数据会发送到 <form> 标签的 action 属性中指定的文件。在本例中,我们指定文件本身来处理表单数据。如果您希望使用另一个 PHP 页面来处理表单数据,请用更改为您选择的文件名。然后,我们可以使用超全局变量 $_POST 来收集输入字段的值:
Instance
<html><body><formmethod="post"action="
"><inputtype="text"name="fname"><inputtype="submit">
form>
$name = $_POST['fname']; echo$name; ?>
body>
html>
PHP $_get
PHP $_GET 也可用于收集提交 HTML 表单 (method="get") 之后的表单数据。$_GET 也可以收集 URL 中的发送的数据。
Let's say we have a page with a hyperlink with parameters:
<html><body><ahref="test_get.php?subject=PHP&web=W3school.com.cn">测试 $GET
a>
body>
html>
"Test $GET""subject""web""test_get.php"$_GET"test_get.php""test_get.php" 中的代码:实例
<html><body>
echo"Study " . $_GET['subject'] . " at " . $_GET['web'];?>
body>
html>
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