Use dynamic web skills PHP native verification code picture source code

Use dynamic web skills PHP native verification code picture source code // random native string // verification code picture width // verification code picture height

File a. php

// CheckNum. php
Session_start ();
Function random ($ len)
{
$ Srcstr = \ "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 \";
Mt_srand ();
$ Strs = \"\";
For ($ I = 0; $ I <$ len; $ I ){
$ Strs. = $ srcstr [mt_rand (0, 35)];
}
Return strtoupper ($ strs );
}
$ Str = random (4); // random natural string
$ Width = 50; // the image width of the verification code
$ Height = 25; // height of the verification code Image
@ Header (\ "Content-Type: image/png \");
$ _ SESSION [\ "code \"] = $ str;
// Echo $ str;
$ Im = imagecreate ($ width, $ height );
// Back the landscape
$ Back = imagecolorallocate ($ im, 0xFF, 0xFF, 0xFF );
// Mixed color
$ Pix = imagecolorallocate ($ im, 187,230,247 );
// Font color
$ Font = imagecolorallocate ($ im, 41,163,238 );
// Draw the point of obfuscation
Mt_srand ();
For ($ I = 0; I I <1000; $ I)
{
Imagesetpixel ($ im, mt_rand (0, $ width), mt_rand (0, $ height), $ pix );
}
Imagestring ($ im, 5, 7, 5, $ str, $ font );
Imagerectangle ($ im, 0, 0, $ width-1, $ height-1, $ font );
Imagepng ($ im );
Imagedestroy ($ im );
$ _ SESSION [\ "code \"] = $ str;
?>

File B. php

Session_start ();
Echo \ "\"; // natural image
Echo $ _ SESSION [\ "code \"]; // natural verification code value
?>