What are external variables of PHP constants and variables? Will you use it? How many other constants do you know?-PHP Problem-php.cn

What are external variables of PHP constants and variables? Will you use it? How many other constants do you know?

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Release： 2023-03-09 21:20:02

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The previous article introduced you to "Do you know PHP constants and variables? How to use it? ? ? 》, this article continues to introduce PHP constants and external variables to you, follow my steps and start together! ! !

What are external variables of PHP constants and variables? Will you use it? How many other constants do you know?

##External variables of PHP constants and variables:

External variables: External variables are some variables specified by PHP during use;

For example: we put the following code in a form and name it user .html:

The code is as follows:

<html>
<head>
</head>
<body>
     <form action="" method="get">
          <input type="text" name="username"/>
          <input type="password" name="pwd"/>
          <input type="submit" value="提交"/>
          </form>

</body>
</html>

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The code execution result is as follows:

What are external variables of PHP constants and variables? Will you use it? How many other constants do you know?

The above code is the most basic piece of code in HTML. Again In the code, the meaning is to send the user and password to reg.php using the

get method. reg.php accepts the two values of username and password passed by the user;

thus obtains the

first external variable: $_GET

$ The main function of _GET is to get the data passed by the value;

Create a new form: named reg.php, use $_GET to accept the value:

Code As shown below:

<html>
<head>
</head>
<body>
     <form action="" method="get">
          <input type="text" name="username"/>
          <input type="password" name="pwd"/>
          <input type="submit" value="提交"/>
          </form>

</body>
</html>
的值
    var_dump($_GET['username']);
?>

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The code is as follows:

What are external variables of PHP constants and variables? Will you use it? How many other constants do you know?

Regarding the $_GET value, you will see the password in the address bar. If you don’t want others to Seeing the password, we need to change $_GET to $_POST in the

PHP code:

The code is as follows:

<html>
<head>
</head>
<body>
     <form action="" method="post">
          <input type="text" name="username"/>
          <input type="password" name="pwd"/>
          <input type="submit" value="提交"/>
          </form>

</body>
</html>
<?php
//$_POST后面加上中括号，将username作为字符串放在中括号里面，
//就得到了表单里面的<input type="text" name="username"/>的值
    var_dump($_POST[&#39;pwd&#39;]);
?>

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The code is as follows:

What are external variables of PHP constants and variables? Will you use it? How many other constants do you know?

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