PHP generated image verification code-with five kinds of verification code, _php tutorial

PHP generated image verification code-with five kinds of verification code,

Previous output verification code used a method, in the foreground with JS generated verification code string, and then passed to the background with PHP output verification code image. In this way, you do not need to use $_session to pass the verification code value, directly with the JS comparison between the generated string and the input string is equal.

In this paper, we demonstrate 5 kinds of verification codes, and describe the function of generating verification code. PHP generated Verification code principle: Through the GD library, generate a picture with a verification code, and save the Verification code in the session.

1. HTML

5 The code is as follows:

1. Digital Verification Code
Verification Code:
  

2, Digital + Letter verification Code
Verification Code:
  

3. Chinese Verification Code
Verification Code:
  

4, imitation Google verification code
Verification Code:
  

5. Arithmetic Verification Code
Verification Code:

2. JS Verification

$ (function () {$ ("#getcode_num"). Click (function () {//Digital authentication $ (this). attr ("src", ' code_num.php ' + math.random ());}); $ (" #chk_num "). Click (function () {var code_num = $ (" #code_num "). Val (); $.post (" Chk_code.php?act=num ", {  code:code_num }, Function (msg) {  if (msg = = 1) {  alert ("The CAPTCHA is correct!") ");  } else {  alert ("CAPTCHA Error! ");  } }); });

Digital + Letter Verification

$ ("#getcode_char"). Click (function () {$ (this). attr ("src", ' code_char.php ' + math.random ());}); $ ("#chk_char"). Click (function () {var Code_char = $ ("#code_char"). Val (); $.post ("Chk_code.php?act=char", {  code: Code_char}, Function (msg) {  if (msg = = 1) {  alert ("The CAPTCHA is correct!") ");  } else {  alert ("CAPTCHA Error! ");  } }); });

Chinese Verification Code

$ ("#getcode_zh"). Click (function () {$ (this). attr ("src", ' code_zh.php ' + math.random ());}); $ ("#chk_zh"). Click (function () {var Code_zh = Escape ($ ("#code_zh"). Val ()); $.post ("Chk_code.php?act=zh", {  code: Code_zh}, Function (msg) {  if (msg = = 1) {  alert ("The CAPTCHA is correct!") ");  } else {  alert ("CAPTCHA Error! ");  } }); });

Google authentication

$ ("#getcode_gg"). Click (function () {$ (this). attr ("src", ' code_gg.php ' + math.random ());}); $ ("#chk_gg"). Click (function () {var code_gg = $ ("#code_gg"). Val (); $.post ("Chk_code.php?act=gg", {  code:code_gg}, Function (msg) {  if (msg = = 1) {  alert ("The CAPTCHA is correct!") ");  } else {  alert ("CAPTCHA Error! ");  } }); });

//Arithmetic verification

$ ("#getcode_math"). Click (function () {$ (this). attr ("src", ' code_math.php ' + math.random ());}); $ ("#chk_math"). Click (function () {var Code_math = $ ("#code_math"). Val (); $.post ("Chk_code.php?act=math", {  code: Code_math}, Function (msg) {  if (msg = = 1) {  alert ("The CAPTCHA is correct!") ");  } else {  alert ("CAPTCHA Error! ");  } }); });});

3, PHP generated verification code

Session_Start (); GetCode (4,60,20); function GetCode ($num, $w, $h) {$code = ""; for ($i = 0; $i < $num; $i + +) {$code. = rand (0, 9);}//4-bit verification code can also be generated directly with Rand (1000,9999)//To write the generated verification code to the session, for verification with $_sessio n["Helloweba_num"] = $code; Create a picture, define the color value header ("Content-type:image/png"); $im = Imagecreate ($w, $h); $black = imagecolorallocate ($im, 0, 0, 0); $gray = Imagecolorallocate ($im, 200, 200, 200); $bgcolor = Imagecolorallocate ($im, 255, 255, 255); Fill Background imagefill ($im, 0, 0, $gray); Draw Border Imagerectangle ($im, 0, 0, $w-1, $h-1, $black); Randomly draws two dashed lines, acts as a disturbance $style = Array ($black, $black, $black, $black, $black, $gray, $gray, $gray, $gray, $gray); Imagesetstyle ($im, $style); $y 1 = rand (0, $h); $y 2 = rand (0, $h); $y 3 = rand (0, $h); $y 4 = rand (0, $h); Imageline ($im, 0, $y 1, $w, $y 3, img_color_styled); Imageline ($im, 0, $y 2, $w, $y 4, img_color_styled); A large number of black dots are randomly generated on the canvas, which acts as interference; for ($i = 0; $i <, $i + +) {Imagesetpixel ($im, rand (0, $w), rand (0, $h), $black), and//numbers are randomly displayed on the canvas, and the horizontal spacing and position of the characters are in accordance with the range of fluctuations Machine Generation $strx = Rand(3, 8); for ($i = 0; $i < $num; $i + +) {$strpos = rand (1, 6); Imagestring ($im, 5, $strx, $strpos, substr ($code, $i, 1), $black) ; $strx + = rand (8, 12); } imagepng ($im);//Output Picture Imagedestroy ($im);//release Image Memory}

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