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This article mainly introduces "how to achieve school inspection in php". In daily operation, I believe many people have doubts about how to achieve school inspection in php. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about "how to achieve school inspection in php". Next, please follow the editor to study!

Php to achieve verification methods: 1, declare "session_start ();" function; 2, create the code for CAPTCHA implementation; 3, declare an empty variable before CAPTCHA implementation, which is used to store CAPTCHA; 4, use POST to receive CAPTCHA.

This article operating environment: Windows7 system, PHP7.1, Dell G3 computer.

How to realize the school inspection by php?

Implementation of CAPTCHA verification function by PHP

The verification of CAPTCHA is realized by using the function of SESSION in PHP.

Declare the function session_start () at the top; tell the server that we want to use the functionality of this function.

Session_start ()

The next thing we use is the code for the CAPTCHA implementation. Here we use the code of English numbers as an example.

$image = imagecreatetruecolor (100,30); / / create a 100 × 30 canvas $white = imagecolorallocate ($image,255255255); / / White imagefill ($image,0,0,$white); / / cover the black canvas

Then declare an empty variable to store the CAPTCHA before the CAPTCHA implementation.

$session = ""; / / empty variable, which stores the CAPTCHA code for ($iCAPTCHA / CAPTCHA

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