How to implement the verification code in php. how to implement the verification code in php?

Teach you how to implement the verification code in php and implement the verification code in php. It is inconvenient to teach you how to implement a verification code in php. more and more verification codes are implemented in forms, so I learned how to implement the verification code in php and how to implement the verification code in php.

More and more verification codes are implemented in forms, but it is inconvenient to use the verification codes written in js. Therefore, I learned the verification codes implemented by php. Well, there is nothing to do, but I don't want to waste time, so I learned how to implement the verification code in php. This is what we call it. In addition, it can also be encapsulated into a function, which will be convenient to use in the future. of course, it is not encapsulated now.

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

If you are a beginner, we recommend that you follow the notes/numbers in my code step by step. The simplest method is to copy the entire code.

Create a new captcha. php:

Php // 10> set the session, which must be at the top of the script session_start (); $ image = imagecreatetruecolor (100, 30 ); // 1> function for setting the verification code image size // 5> set the verification code color imagecolorallocate (int im, int red, int green, int blue); $ bgcolor = imagecolorallocate ($ image, 255,255,255); // # ffffff // 6> fill in the area where int imagefill (int im, int x, int y, int col) (x, y) is located, col indicates the color of imagefill ($ image, 0, 0, $ bgcolor) to be coated. // 10> set the variable $ captcha_code = ""; // 7> generate random numbers for ($ I = 0; $ I <4; $ I ++) {// set the font size $ fontsize = 6; // set the font color, random color $ fontcolor = imagecolorallocate ($ image, rand (0,120), rand (0,120), rand (0,120 )); // 0-120 deep color // set the number $ fontcontent = rand (); // 10>. = continuous definition variable $ captcha_code. = $ fontcontent; // Set coordinates $ x = ($ I * 100/4) + rand (); $ y = rand (); imagestring ($ image, $ fontsize, $ x, $ y, $ fontcontent, $ fontcolor);} // 10> save to session $ _ SESSION ['authcode'] = $ captcha_code; // 8> add interference elements, set snowflake points for ($ I = 0; $ I <200; $ I ++) {// set the color of the point. The color of 50-is lighter than the number, read $ pointcolor = imagecolorallocate ($ image, rand (50,200), rand (50,200), rand (50,200); // imagesetpixel-draw a single pixel imagesetpixel ($ image, rand (), rand (), $ pointcolor);} // 9> add interference elements and set the horizontal line for ($ I = 0; $ I <4; $ I ++) {// set the line color $ linecolor = imagecolorallocate ($ image, rand (80,220), rand (80,220), rand (80,220 )); // set the line, 2.1 line imageline ($ image, rand (), $ linecolor );} // 2> set the header, image/png header ('content-Type: image/png '); // 3> imagepng () create a png image function imagepng ($ image ); // 4> imagedestroy () end graph function destroy $ image imagedestroy ($ image );

The code for the static page is: index.html

       
      
  Confirm the verification code title> head>    
        
   
Verification code: 'style = "width: 100px; height: 30px"/> for another? A> p>
   
Enter the verification code:P>
   
P>
  
 

As you can see from index.html, the submitted form is in form. php, so there is also a judgment form. php code:

Php header ("Content-Type: text/html; charset = utf-8"); // Set the header information // isset () check if the variable is set if (isset ($ _ REQUEST ['authcode']) {session_start (); // strtolower () lower case function if (strtolower ($ _ REQUEST ['authcode']) ==$ _ SESSION ['authcode']) {// jump to the page echo"