Now start to generate a variety of PHP verification code journey, novice to drive, please swipe!
First of all, let's start mister into a background image with a CAPTCHA
Note: There is no imagejpg () function, only the imagepng () function
Imagecreatetruecolor () function meaning
Effect
Considering the background image of our general verification code is white, we will now change the background image
Effect
Correlation function meaning
Note: before outputting a picture, we have to generate the header ("Content-type:image/png"), which tells the server to output a picture
First, generate a pure digital verification code
1. The code part that produces the number
Effect
Related functions
Sets the color of the number to random
Effect
Note: control font size and distribution, avoid font overlap or font display (i.e. control the definition of x and y axes)
2, increase the interference element (point Element)
Code section
Effect
Related functions
3. Add interference element (line Element)
Effect
Related functions
Note: interference information must control the color, avoid the color bar number to cover the
Second, the generation of alphanumeric verification code
1, first of all the relevant settings of the pure number to comment out, to avoid interference
Code section
Effect
Tip: We can filter the displayed content, such as the number 0 and the letter O is similar, can be deleted (the letter L and the number 1, the letter Z and the number 2), so that users have a better experience
Note: Sometimes we filter to filter an empty content, the verification code will appear only three or three characters or less, then we can avoid
Third, through seseion storage user authentication information
1, first of all, we know that when we want to use the session to store information, we will be in the PHP file at the top of the session to open
Secondly, we need to store with the session, then:
2, verification code submitted through the form, check
Form Code Section
Effect
Code that validates the background after the user submits the verification code (written at the top of the form.php)
Test
Setting case-insensitive validation
Four, dynamic calibration design
1. Code part
Effect
Five, image verification Code
1. Code part
2. Front-End part
Effect
Six, Chinese character Verification code
1, the Chinese character verification code and the alphanumeric verification code is similar, the slight modification is good, the code part
Effect
Front-end Section
Effect
2, the need for more information on Chinese characters
The front end is the same
Effect
Related functions
Note: Select the font style to support Chinese, such as simplified, bold and so on
The above is the relevant verification code implementation content, you learned it!!! Come on
END
Generate random number verification codes for pure numbers, alphanumeric, images, and pure Chinese characters via PHP