PHP verification code generation procedure _ PHP Tutorial

PHP verification code generation program methods. PHP verification code is a basic function of security verification when users register for logon or publish information, the following section describes some common PHP verification code generation and PHP verification code generation functions. This function is commonly used to provide a basic security verification function when users register for logon or publish information, the following small series will introduce some common PHP verification code generation code and application instances.

Example 1: Use arrays directly. this method is relatively simple.

The code is as follows:

$ Arr = array (2, 3, 4, 5, 8, 1, 9, 7, "a", "B", "c", "d", "e", "f ", "Medium", "country", "South", "North", "big", "small", "more", "less "); $ B = array_rand ($ arr, 3 ); ?> Echo "code :"; Foreach ($ B as $ key) { Echo $ arr [$ key]; } ?> (Save the preceding statement as a php file) Header ("Content-Type: text/html; charset = utf-8 "); Echo $ _ POST ["yanzhengma"]; Echo $ _ POST ["code"]; If ($ _ POST ["yanzhengma"] == _ POST ["code"]) { Echo "the verification code is correct "; } Else { Die ("script" alert ('incorrect verification code "); location =" array_rand.php "; script"); } ?>

(Save the preceding statement as yz. php)

Example 2: Use arrays instead of a little more data.

The code is as follows:

Function UPCAbarcode ($ code ){ $ Lw = 2; $ hi = 100; $ Lencode = array ('20140901', '20160901', '20160901', '20160301', '20160301 ', '123', '123', '123', '123', '123 '); $ Rencode = array ('20140901', '20160901', '20160901', '20160301', '20160301 ', '123', '123', '123', '123', '123 '); $ Ends = '20180101'; $ center = '20180101 '; /* UPC-A Must be 11 digits, we compute the checksum .*/ If (strlen ($ code )! = 11) {die ("UPC-A Must be 11 digits .");} /* Compute the EAN-13 Checksum digit */ $ Ncode = '0'. $ code; $ Even = 0; $ odd = 0; For ($ x = 0; $ x <12; $ x ++ ){ If ($ x % 2) {$ odd + = $ ncode [$ x];} else {$ even + = $ ncode [$ x];} } $ Code. = (10-($ odd * 3 + $ even) % 10) % 10; /* Create the bar encoding using a binary string */ $ Bars = $ ends; $ Bars. = $ Lencode [$ code [0]; For ($ x = 1; $ x <6; $ x ++ ){ $ Bars. = $ Lencode [$ code [$ x]; } $ Bars. = $ center; For ($ x = 6; $ x <12; $ x ++ ){ $ Bars. = $ Rencode [$ code [$ x]; } $ Bars. = $ ends; /* Generate the Barcode Image */ $ Img = ImageCreate ($ lw * 95 + 30, $ hi + 30 ); $ Fg = ImageColorAllocate ($ img, 0, 0, 0 ); $ Bg = ImageColorAllocate ($ img, 255,255,255 ); ImageFilledRectangle ($ img, 0, 0, $ lw * 95 + 30, $ hi + 30, $ bg ); $ Shift = 10; For ($ x = 0; $ x if ($ x <10) | ($ x >=45 & $ x <50) | ($ x> = 85) {$ sh = 10;} else {$ sh = 0 ;} If ($ bars [$ x] = '1') {$ color = $ fg;} else {$ color = $ bg ;} ImageFilledRectangle ($ img, ($ x * $ lw) + 15, 5, ($ x + 1) * $ lw + 14, $ hi + 5 + $ sh, $ color ); } /* Add the Human Readable Label */ ImageString ($ img, 4,5, $ hi-5, $ code [0], $ fg ); For ($ x = 0; $ x <5; $ x ++ ){ ImageString ($ img, 5, $ lw * (13 + $ x * 6) + 15, $ hi + 5, $ code [$ x + 1], $ fg ); ImageString ($ img, 5, $ lw * (53 + $ x * 6) + 15, $ hi + 5, $ code [$ x + 6], $ fg ); } ImageString ($ img, 4, $ lw * 95 + 17, $ hi-5, $ code [11], $ fg ); /* Output the Header and Content .*/ Header ("Content-Type: image/png "); ImagePNG ($ img ); } UPCAbarcode ('20140901 '); ?>

Example 3: A Complete ajax refresh verification code instance

Vcode. php

The code is as follows:

Session_start (); // enable the session function Header ("Cache-Control: no-cache, must-revalidate "); $ Im = imagecreate (60, 30); // you can specify the image width and height. $ Vcode = getVCode (); // get the characters to be displayed $ Bg = imagecolorallocate ($ im, 255,255,255); // define the image background $ Txt = imagecolorallocate ($ im, rand (0,255), rand (0,255), rand (0,255); // defines the color of the characters to be displayed Imagestring ($ im, 8, 0, 0, $ vcode, $ txt); // write a string to the image Header (Content-type: image/jpeg); // Define Content-type Imagejpeg ($ im); // display images in JPEG format $ _ SESSION [vcode] = $ vcode; // write to the SESSION Function getVCode () {// randomly generates a specified number of strings. $ Codenum = 4; $ Checkcode = ""; $ String = ""; // optional string to be displayed, please define it yourself; For ($ I = 0; $ I <$ codenum; $ I ){ $ Number = rand (0, 2 ); Switch ($ number) {// can be flexibly defined based on optional strings; Case 0: $ rand_number = rand (0, 10); break; Case 1: $ rand_number = rand (11, 36); break; Case 2: $ rand_number = rand (37,62); break; } $ Code = substr ($ string, $ rand_number, 1 ); $ Checkcode = $ checkcode. $ code; } Return $ checkcode; } ?>

Loginform.html

The code is as follows:

Vcode. js

The code is as follows:

// This function is used to obtain the verification code. Function getVCode (){ Var vcode = document. getElementById ('vcode '); Vcode. src = 'vcode. php? Nocache = '+ new Date (). getTime (); } // This function is used to verify the verification code Function usrVCode (){ If (! CheckLogin () return false; Var loginvcode = document. loginform. loginvcode. value; Var xmlhttp1 = createAjax (); Var data = '& loginvcode =' + loginvcode; If (xmlhttp1 ){ Var state = document. getElementById ('state '); Xmlhttp1.open ('GET ',? Do = vcodedo '+ data, true ); Xmlhttp1.send (null ); Xmlhttp1.onreadystatechange = function (){ If (xmlhttp1.readyState = 4 & xmlhttp1.status = 200 ){ SetTimeout ("state. style. display = 'none';", 1000 ); Var myres = xmlhttp1.responseText; Var result = (myres = 1 )? "Congratulations, the verification code is entered correctly! ":" Sorry, incorrect verification code! "; If (myres = 0) alert (result ); If (myres = 1) usrLogin (); } Else { State. style. display = ""; State. style. left = (document. body. offsetWidth-350)/2; State. style. top = (document. body. offsetHeight-235)/2 + document. body. scrollTop; } } } }

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