PHP Verification Code Generation program several methods _php tutorial

PHP Authentication Code Students This function is often used to sign in or publish information with the user a basic function of security verification, the following small part to introduce some common PHP code generation codes and application examples.

Example 1, using arrays directly, this method is relatively simple

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!--? php $arr =array (2,3,4,5,8,1,9,7," a "," B "," C "," D "," E "," F "," Zhong "," Country "," South " , "North", "Big", "small", "more", "less"); $b =array_rand ($arr, 3); ? !--? php Echo "code:"; foreach ($b as $key) { echo $arr [$key]; } ? (Save the above statement as a PHP file) !--? php header ("Content-type:text/html;charset=utf-8"); echo $_post["Yanzhengma"]; Echo $_post["code"]; if ($_post["Yanzhengma"]==$_post["Code"]) { echo "captcha is correct"; } Else { Die (""); } ?

(Save the above statement as yz.php)

Example 2, but also with the array is not the data a little more

The code is as follows

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function Upcabarcode ($code) { $LW = 2; $hi = 100; $Lencode = Array (' 0001101 ', ' 0011001 ', ' 0010011 ', ' 0111101 ', ' 0100011 ', ' 0110001 ', ' 0101111 ', ' 0111011 ', ' 0110111 ', ' 0001011 '); $Rencode = Array (' 1110010 ', ' 1100110 ', ' 1101100 ', ' 1000010 ', ' 1011100 ', ' 1001110 ', ' 1010000 ', ' 1000100 ', ' 1001000 ', ' 1110100 '); $ends = ' 101 '; $center = ' 01010 '; /* upc-a must be one digits, we compute the checksum. */ if (strlen ($code)! = one) {die ("upc-a must is one 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];} } $code. = (($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 [one], $FG); /* Output the Header and Content. */ Header ("Content-type:image/png"); Imagepng ($IMG); } Upcabarcode (' 12345678901 '); ?>

Example 3, this is a more complete Ajax refresh Captcha instance

vcode.php

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!--? php session_start ();//Open Session function Header ("Cache-control:no-cache, must-revalidate"); $im = Imagecreate (60,30);//define picture width and height $vcode =getvcode ();//Gets the character to display $BG = Imagecolorallocate ($im, 255, 255, 255);//define Picture background $txt = Imagecolorallocate ($im, Rand (0,255), Rand (0,255), Rand (0,255));//define the color to display characters Imagestring ($im, 8, 0, 0, $vcode, $txt);//write String to Picture Header (content-type:image/jpeg);//Definition Content-type Imagejpeg ($im);//display pictures in JPEG format $_session[vcode]= $vcode;//write SESSION function Getvcode () {//randomly generate a user-specified number of strings $codenum = 4; $checkcode = ""; $string = "";//the optional string to be displayed, please define it yourself; for ($i =0; $i < $codenum; $i) { $number =rand (0,2); Switch ($number) {//can be flexibly defined based on an optional string; Case 0: $rand _number=rand (0,10); Case 1: $rand _number=rand (11,36); Case 2: $rand _number=rand (37,62); } $code =substr ($string, $rand _number,1); $checkcode = $checkcode. $code; } return $checkcode; } ?>

Loginform.html

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Vcode.js

The code is as follows

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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, the CAPTCHA was entered incorrectly! "; 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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