Php verification code generation function, php verification code generation _ PHP Tutorial

Php generates the verification code function, and php generates the verification code. Php generates the verification code function. php generates the verification code. php generates the verification code function, which is practical and reliable. The verification code generated first and foremost (here, the example of a full-number verification code is generated. the verification code function is generated by php, and the verification code is generated by php.

Php functions for generating verification codes are practical and reliable. The verification code generated first and foremost (the example of the verification code with full numbers is generated here ):

The following is the source code of the php verification code:

<? Php session_start (); // session_register ('checkcode'); // for PHP4.2 or later versions, you do not need to use session_register () to register the SESSION variable $ type = 'GIF'; $ width = 45; $ height = 20; header ("Content-type: image /". $ type); srand (double) microtime () * 1000000); if (isset ($ _ GET ['action']) {$ randval = randStr (4, $ _ GET ['action']);} else {$ randval = randStr (4, '');} if ($ type! = 'GIF' & function_exists ('imagecreatetruecolor') {$ im = @ imagecreatetruecolor ($ width, $ height);} else {$ im = @ imagecreate ($ width, $ height) ;}$ r = Array (225,211,255,223); $ g = Array (225,236,237,215); $ B = Array (225,236,166,125); $ key = rand ); $ backColor = ImageColorAllocate ($ im, $ r [$ key], $ g [$ key], $ B [$ key]); // background color (random) $ borderColor = ImageColorAllocate ($ im, 127,157,185); // border color $ pointColor = ImageColorAllocate ($ im, 255,170,255); // The dot color @ imagefilledrectangle ($ im, $ width-1, $ height-1, $ backColor); // background position @ imagerectangle ($ im, 0, 0, $ width-1, $ height-1, $ borderColor ); // border position $ stringColor = ImageColorAllocate ($ im, 255, 51, 153); for ($ I = 0; $ I <= 100; $ I ++) {$ pointX = rand (2, $ width-2); $ pointY = rand (2, $ height-2); @ imagesetpixel ($ im, $ pointX, $ pointY, $ pointColor) ;}@ imagestring ($ im, 5, 5, 1, $ randval, $ stringColor); $ ImageFun = 'image '. $ type; $ ImageFun ($ im); @ imagedestroy ($ im); $ _ SESSION ['checkcode'] = $ randval; function randStr ($ len = 6, $ format = 'all') {switch ($ format) {case 'all': // Generate a verification code containing digits and letters $ chars = 'callback'; break; case 'char ': // only generate the verification code containing letters $ chars = 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz'; break; case 'number ': // Generate a verification code containing only numbers $ chars = '20160301'; break; default: $ chars = '2016'; break;} $ string = ''; while (strlen ($ string) <$ len) $ string. = substr ($ chars, (mt_rand () % strlen ($ chars), 1); return $ string ;}

For details about how to use this function, see the following example (here is the verification code for generating full numbers ):

The above is the implementation function for php to generate the verification code. I hope it will be helpful for you to learn.

Php generates the verification code function, which is practical and reliable. The verification code generated up and down first (the example effect of the verification code with full numbers is generated here...