Verification Code class and usage in PHP

 

Note: add the public page to session_start ();

 

<? Php

Session_start ();

Ini_set ('display _ errors ', 'off ');

Class CCheckCodeFile

{

// Number of digits of the Verification Code www.2cto.com

 

Var $ mCheckCodeNum = 4;

 

// Generated Verification Code

Var $ mCheckCode = '';

 

// Verification Code Image

Var $ mCheckImage = '';

 

// Interference Pixel

Var $ mDisturbColor = '';

 

// The image width of the Verification Code

Var $ mCheckImageWidth = '80 ';

 

// The image width of the Verification Code

Var $ mCheckImageHeight = '20 ';

 

// Output Header

Function OutFileHeader ()

{

Header ("Content-type: image/png ");

}

 

// Generate a verification code

Function CreateCheckCode ()

{

// $ This-> mCheckCode = strtoupper (substr (md5 (rand (), 0, $ this-> mCheckCodeNum ));

$ This-> mCheckCode = strtoupper (substr (rand (0,999999999999), 0, $ this-> mCheckCodeNum ));

Session_cache_expire (60 );

Session_start ();

$ _ SESSION ["code_str"] = $ this-> mCheckCode;

Return $ this-> mCheckCode;

}

 

// Generate a verification code Image

Function CreateImage ()

{

$ This-> mCheckImage = @ imagecreate ($ this-> mCheckImageWidth, $ this-> mCheckImageHeight );

Imagecolorallocate ($ this-> mCheckImage, 255,255,255 );

Return $ this-> mCheckImage;

}

 

// Sets the interference pixels of the image.

Function SetDisturbColor ()

{

For ($ I = 0; $ I <= 128; $ I ++)

{

$ This-> mDisturbColor = imagecolorallocate ($ this-> mCheckImage, rand (0,255), rand (0,255), rand (0,255 ));

Imagesetpixel ($ this-> mCheckImage, rand (1,100), rand (1,100), $ this-> mDisturbColor );

}

}

 

// Set the size, width, and height of the Verification Code image.

Function SetCheckImageWH ($ width, $ height)

{

If ($ width = ''| $ height ='') return false;

$ This-> mCheckImageWidth = $ width;

$ This-> mCheckImageHeight = $ height;

Return true;

}

 

// Upload the verification code one by one on the Verification Code Image

Function WriteCheckCodeToImage ()

{

For ($ I = 0; $ I <= $ this-> mCheckCodeNum; $ I ++)

{

$ Bg_color = imagecolorallocate ($ this-> mCheckImage, rand (0,255), rand (0,255), rand (0,255 ));

$ X = floor ($ this-> mCheckImageWidth/$ this-> mCheckCodeNum) * $ I;

$ Y = rand (0, $ this-> mCheckImageHeight-15 );

Imagechar ($ this-> mCheckImage, 5, $ x, $ y, $ this-> mCheckCode [$ I], $ bg_color );

}

}

 

// Output the verification code Image

Function OutCheckImage ()

{

$ This-> OutFileHeader ();

$ This-> CreateCheckCode ();

$ This-> CreateImage ();

$ This-> SetDisturbColor ();

$ This-> WriteCheckCodeToImage ();

Imagepng ($ this-> mCheckImage );

Imagedestroy ($ this-> mCheckImage );

}

}

 

$ C_check_code_image = new CCheckCodeFile ();

// $ C_check_code_image-> SetCheckImageWH (, 50); // you can specify the image size of the verification code.

$ C_check_code_image-> OutCheckImage ();

?>

 

 

 

Usage:

<Tr>

<Td align = "center" valign = "middle"> Verification Code </td>

<Td align = "center" valign = "middle"> <input name = "number" type = "text" style = "width: 80px;">

</Td>

</Tr>

 

 

Verify if it is correct

 

Session_start ();

 

If ($ _ POST ["number"] ==$ _ SESSION ["code_str"]) {

// Echo ("the verification code is correct ");

} Else {

Echo"

 

<Script>

 

Var s = 10;

 

Function OK ()

 

{

 

S --;

 

Document. getElementById ('tids'). innerHTML = s;

 

If (s = 0)

 

{

 

ClearTimeout (t );

 

History. go (-1 );

 

}

 

}

 

Var t = setInterval ('OK ()', 1000 );

 

</Script>

 

". "Enter the verification code. Please re-enter <span id = 'tids'> </span> seconds to jump to <a href = \" javascript: history. go (-1) \ "> previous page </a> ";

}

 

From http://itsafe.org /? P = 384