Teach you PHP how to implement verification code _php instance

Verification code in the form to achieve more and more, but with JS write the verification code, always feel inconvenient, so learn the next PHP implementation of the verification code. Well, there is nothing to do, but do not want to waste time, so learn the next PHP implementation verification code. Is the so-called, more than the pressure of the body. Also, it can be encapsulated into a function, it is convenient to use later, of course, now not encapsulated.

Now let's talk about simple, pure digital verification code.

If it's a beginner, it's recommended to follow my code's comments/numbers step by step. The easiest way to do this is to copy the entire code away.

Create a new captcha.php:

PHP//10> set session, must be at the top of the script session_start ();    $image = Imagecreatetruecolor (100, 30);
  1> a function to set the size of the CAPTCHA image//5> set the captcha color imagecolorallocate (int im, int red, int green, int blue); $bgcolor = Imagecolorallocate ($image, 255,255,255); #ffffff//6> Area fills the area of the int imagefill (int im, int x, int y, int col) (x,y), and Col represents the color to be painted Imagefill ($image, 0, 0,
  $bgcolor);
  10> Set Variable $captcha _code = "";    
    7> generates a random number for ($i =0; $i <4; $i + +) {//set font size $fontsize = 6;      Set font color, random color $fontcolor = imagecolorallocate ($image, Rand (0,120), Rand (0,120), Rand (0,120));
    0-120 Deep Color//Set Number $fontcontent = rand (0,9);  
    10>.= continuously defines variables $captcha _code. = $fontcontent;
    Set the coordinates $x = ($i *100/4) +rand (5,10);

    $y = rand (5,10);
  Imagestring ($image, $fontsize, $x, $y, $fontcontent, $fontcolor);
  //10> Save to session $_session[' authcode ' = $captcha _code; 8> add interference elements, set snowflake point for ($i =0; $i <200; $i + +) {//Set the color of the point, 50-200 color is lighter than the number, do not interfere with reading $POINTCOlor = Imagecolorallocate ($image, Rand (50,200), Rand (50,200), Rand (50,200));
  Imagesetpixel-draws a single pixel Imagesetpixel ($image, Rand (1,99), Rand (1,29), $pointcolor); //9> add interference elements, set horizontal for ($i =0 $i <4; $i + +) {//set line Color $linecolor = Imagecolorallocate ($image, Rand (80,220), ran
    D (80,220), Rand (80,220));
  Set line, 2.1-line Imageline ($image, Rand (1,99), Rand (1,29), Rand (1,99), Rand (1,29), $linecolor);
  //2> set Head, image/png header (' content-type:image/png ');
  3>imagepng () set up PNG graphics function imagepng ($image);

 4>imagedestroy () ends the graphics function to destroy $image Imagedestroy ($image);

Then there is the code for the static page: index.html

<doctype html>
 
 

As you can see from the index.html, the submitted form is to form.php, so there's a form.php code to judge:

PHP
  Header ("Content-type:text/html;charset=utf-8");      Set Header information
  //isset () detect if the variable is set to
  if (isset ($_request[' Authcode ')) {
    session_start ();
    Strtolower () lowercase function
    if (strtolower ($_request[' authcode ')) = = $_session[' Authcode ']) {
      //jump page
      Echo < Script language=\ "javascript\" >;
      echo "document.location=\"./form.php\ "";
      echo "</script>";
    } else{
      //Tips as well as jump page
      echo "<script language=\" javascript\ ">";
      echo "Alert (' Input error! ');";
      echo "document.location=\"./form.php\ "";
      echo "</script>";
    }
    Exit ();
  }

The display page is as follows:

Then, the realization of pure numbers, the number plus English should not be difficult. The code to be modified is just captcha.php the//7> generate random numbers to//7> generate random letters and numbers, if you really cute to modify these words to think that can be achieved, then congratulate you, you always keep happy. Children with brain remnants are much more cheerful.

Don't say much nonsense, pull the code bar.

PHP//10> set session, must be at the top of the script session_start ();    $image = Imagecreatetruecolor (100, 30);
  1> a function to set the size of the CAPTCHA image//5> set the captcha color imagecolorallocate (int im, int red, int green, int blue); $bgcolor = Imagecolorallocate ($image, 255,255,255); #ffffff//6> Area fills the area of the int imagefill (int im, int x, int y, int col) (x,y), and Col represents the color to be painted Imagefill ($image, 0, 0,
  $bgcolor);
  10> Set Variable $captcha _code = "";    
    7> generates random letters and numbers for ($i =0; $i <4; $i + +) {//set font size $fontsize = 8;      Set font color, random color $fontcolor = imagecolorallocate ($image, Rand (0,120), Rand (0,120), Rand (0,120));
    0-120 Deep Color/Set the value to be randomly taken, remove error-prone values such as 0 and o $data = ' abcdefghigkmnpqrstuvwxy3456789 ';
    Fetch value, String intercept method strlen gets string length $fontcontent = substr ($data, Rand (0,strlen ($DATA)), 1);    
    10>.= continuously defines variables $captcha _code. = $fontcontent;
    Set the coordinates $x = ($i *100/4) +rand (5,10);

    $y = rand (5,10);
  Imagestring ($image, $fontsize, $x, $y, $fontcontent, $fontcolor); //10> Save to session $_session[' authcode ' = $captcha _code; 8> add interference elements, set snowflake point for ($i =0; $i <200; $i + +) {//Set the color of the point, 50-200 color is lighter than the number, do not interfere with reading $pointcolor = Imagecolorallocate ($imag    
    E,rand (50,200), Rand (50,200), Rand (50,200));
  Imagesetpixel-draws a single pixel Imagesetpixel ($image, Rand (1,99), Rand (1,29), $pointcolor); //9> add interference elements, set horizontal for ($i =0 $i <4; $i + +) {//set line Color $linecolor = Imagecolorallocate ($image, Rand (80,220), ran
    D (80,220), Rand (80,220));
  Set line, 2.1-line Imageline ($image, Rand (1,99), Rand (1,29), Rand (1,99), Rand (1,29), $linecolor);
  //2> set Head, image/png header (' content-type:image/png ');
  3>imagepng () set up PNG graphics function imagepng ($image);

 4>imagedestroy () ends the graphics function to destroy $image Imagedestroy ($image);

The other two pages are not allowed to be modified.

Generally speaking, it is enough now. But like anime, there's always a way out.

So, let's have a Chinese character. In fact, I am also ready to test the Chinese characters to my graduation design inside, although now very popular slide verification code, but I am not specifically learning JS.

And, also can and reply the teacher said, we do not need to verify the code material, even the picture is generated, with their own knowledge of 13, there is no set mody.

PHP//11> set session, must be at the top of the script session_start ();    
  1> a function $image = Imagecreatetruecolor (200, 60) to set the size of the validation code picture;
  5> Set the authentication code color imagecolorallocate (int im, int red, int green, int blue); $bgcolor = Imagecolorallocate ($image, 255,255,255); #ffffff//6> Area fills the area of the int imagefill (int im, int x, int y, int col) (x,y), and Col represents the color to be painted Imagefill ($image, 0, 0,
  $bgcolor); 7> Set TTF Font $fontface = ' fzytk.
  TTF '; 7> set the font, realize a simple digital reserve $str = ' Heaven and earth are unkind to all things and the dog Saints are unkind to the common people as a humble dog this often appears in the accusation of tyranny and brutality that treats everything as a lowly pig dog and those above the so-called holy people are also not the same as our common people also as pigs and dogs as inferior to things but really is to take the interpretation is not emotional personally to all things equal to the Saints not emotional personally to the people Equal to the hand and son of the sons and women when the hero lovingly looked at each other said a sentence to hold the son of the hand and the son of the old woman tearful dim blushing back to a hate this episode we have not seen a lot but let's take a look at this sentence of the original sentence of death and Ze Cheng said that the hands and son to hold the son grow old in sigh broad XI no I live XI Yu Ying XI No I believe it means to say the agreement between the Warriors
  Said to die together now and I agreed to the people are gone how do I live ah naked Brothers and lakes comrades friendship to describe a good base of friends with love than men and women between the right to a lot of it ';  
  Str_split () Cutting string is an array, one Chinese in utf_8 is 3 characters $strdb = Str_split ($str, 3);
  >11 $captcha _code = '; 8> generates random man for ($i =0; $i <4; $i + +) {//Set font color, random color $fontcolor = imagecolorallocate ($image, Rand (0,120), rand (0, ), RAnd (0,120));
    0-120 Deep Color//random selection of Chinese $in = rand (0,count ($STRDB));
    $CN = $strdb [$in];
    Records Chinese to a string that will be saved to the session $captcha _code. = $CN; /*imagettftext (Resource $image, float $size, float $angle, int $x, int $y, int $color, string $fontfile, String $text Curtains, dimensions, angles, coordinates, colors, font paths, text strings Mt_rand () generate better random numbers, faster than rand () four times times * * Imagettftext ($image, Mt_rand (20,24), Mt_rand ( -60,60), (4
  0* $i +20), Mt_rand (30,35), $fontcolor, $fontface, $CN);
  //11> Save to session $_session[' authcode ' = $captcha _code; 9> add interference elements, set point for ($i =0; $i <200; $i + +) {//Set the color of the point, 50-200 color is lighter than the number, do not interfere with reading $pointcolor = Imagecolorallocate ($image,    
    Rand (50,200), Rand (50,200), Rand (50,200));
  Imagesetpixel-draws a single pixel Imagesetpixel ($image, Rand (1,199), Rand (1,59), $pointcolor); //10> add interference element, set line for ($i =0; $i <4; $i + +) {//set line Color $linecolor = Imagecolorallocate ($image, Rand (80,220), ran
    D (80,220), Rand (80,220)); Set line, 2.1-line Imageline ($image, Rand (1,199), Rand (1,59), Rand (1,199), Rand (1,59), $linecolor);
  //2> set Head, image/png header (' content-type:image/png ');
  3>imagepng () set up PNG graphics function imagepng ($image);
 4>imagedestroy () ends the graphics function to destroy $image Imagedestroy ($image);

The effect chart is as follows

The above is the entire content of this article, to help you realize PHP digital verification Code, PHP letter verification Code, PHP Chinese character Verification code, I hope to help you learn.