PHP Verification code in the verification page of the application Analysis _php tutorial

For a website, you will definitely need a page that provides validation functionality. Then we need to consider the application of the verification code in the verification page now. We're going to give you a detailed explanation of the prepare a page to display and submit a PHP verification code

 
 

  
  

  
 Php 
  
  

  
 
  
  

  
@header ("content-type:text/html; CharSet = UTF -8 "); 
  
  

  
 
  
  

  
Open session
  
  

  
 
  
  

  
Session_Start ();
  
  

  
 
  
  

  
?> 
  
  

  
 
  
  

  
< HTML > 
  
  

  
 
  
  

  
 < Head > 
  
  

  
 
  
  

  
 < Meta    http-equiv="Content-type"   Content="text/ html Charset=utf-8 "   /> 
  
  

  
 
  
  

  
 < title >  PHP Verification code example   title>  
  
  

  
 
  
  

  
  Head > 
  
  

  
 
  
  

  
 < Body > 
  
  

  
 
  
  

  
Verification Code:  <br/> 
  
  

  
 
  
  

  
 < iframe    id="iimg"   height="   width =  -   src="img.php"   frameborder="0" > IFrame    >     
  
  

  
 
  
  

  
 < BR /> 
  
  

  
 
  
  

  
 < input    type= button  value="Can't see, change one" onclick = "iimg.location.reload ();"     > 
  
  

  
 
  
  

  
 < BR > 
  
  

  
 
  
  

  
 < form    action="validate.php"   method="POST"  > 
  
  

  
 
  
  

  
Enter the verification code:  <input    name="Imgid"   style="width:60"  > 
  
  

  
 
  
  

  
 < input    type="Submit"   value="OK">  
  
  

  
 
  
  

  
  form > 
  
  

  
 
  
  

  
  Body > 
  
  

  
 
  
  

  
 HTML > 
 
 

Second, the following is the PHP code generation page, the page is called on the first page

 
 

  
  

  
 Php 
  
  

  
 
  
  

  
Header ("Content-type:image/gif");
  
  

  
 
  
  

  
Session_Start ();
  
  

  
 
  
  

  
The verification code is a random character, the following is the algorithm
  
  

  
 
  
  

  
$randval;
  
  

  
 
  
  

  
For ($i=0; $i<7; $i + +) {
  
  

  
 
  
  

  
 $ Randstr  =  Mt_rand (Ord (' A '), Ord (' Z ')); 
  
  

  
 
  
  

  
Srand (Double) microtime () *1000000);
  
  

  
 
  
  

  
 $ RANDV  =  Mt_rand (0,10); 
  
  

  
 
  
  

  
if ($randv%2==0) {
  
  

  
 
  
  

  
 $ Randval. = Mt_rand (0,10); 
  
  

  
 
  
  

  
}else{
  
  

  
 
  
  

  
 $ Randval. = CHR ($RANDSTR); 
  
  

  
 
  
  

  
}
  
  

  
 
  
  

  
}
  
  

  
 
  
  

  
Register PHP verification code to session
  
  

  
 
  
  

  
Session_register ($randval);
  
  

  
 
  
  

  
Here is the drawing of the Verification Code map
  
  

  
 
  
  

  
$ Height  =   - ;//Graph High
  
  

  
 
  
  

  
$ width  =   - ;//Graph width
  
  

  
 
  
  

  
$ im  =  Imagecreatetruecolor ($width, $height); 
  
  

  
 
  
  

  
$  White  =  imagecolorallocate ($im, 255, 255, 255); 
  
  

  
 
  
  

  
$ Blue  =  imagecolorallocate ($im, 0, 0, 64); 
  
  

  
 
  
  

  
Imagefill ($im, 0, 0, $white);
  
  

  
 
  
  

  
Srand (Double) microtime () *1000000000);
  
  

  
 
  
  

  
Imageline ($im, Mt_rand (0, $width/3), Mt_rand (0, $height/3), Mt_rand ($width/3, $width), Mt_rand ($height/3, $height), $ Blue);
  
  

  
 
  
  

  
Srand (Double) microtime () *1000000);
  
  

  
 
  
  

  
Imageline ($im, Mt_rand ($width/3, $width), Mt_rand (0, $height/3), Mt_rand (0, $width/3), Mt_rand (0, $height/3), $blue);
  
  

  
 
  
  

  
Srand (Double) microtime () *1000000);
  
  

  
 
  
  

  
Imagestring ($im, Mt_rand (0, $width-strlen ($randval) *), Mt_rand (0, $height -12), $randval, $blue);
  
  

  
 
  
  

  
Imagegif ($im);
  
  

  
 
  
  

  
Imagedestroy ($im);
  
  

  
 
  
  

  
/*
  
  

  
 
  
  

  
It is important to note that in order to support the above drawing functions, we must load the GD2 graphics processing library in PHP, which can be modified in the php.ini file.
  
  

  
 
  
  

  
; extension = PHP_GD2 . DLL
  
  

  
 
  
  

  
For
  
  

  
 
  
  

  
extension = PHP_GD2 . DLL
  
  

  
 
  
  

  
That opens the GD2 library.
  
  

  
 
  
  

  
*/
  
  

  
 
  
  

  
?> 
 
 

Third, this is the verification page, indicating whether PHP verification code through verification

 
 

  
  

  
  php   @header ("content-type:text/html; CharSet = UTF -8 "); 
  
  

  
 
  
  

  
Open session
  
  

  
 
  
  

  
Session_Start ();
  
  

  
 
  
  

  
Get user-entered verification code and convert to uppercase
  
  

  
 
  
  

  
 $ Imgid_req = $_request[' Imgid ']; 
  
  

  
 
  
  

  
 $ Imgid_req  =  Strtoupper ($imgId _req); 
  
  

  
 
  
  

  
Verify that the string is registered with the session variable
  
  

  
 
  
  

  
if (session_is_registered ($imgId _req)) {
  
  

  
 
  
  

  
echo "  <font    color= blue  > verified!    font> "; 
  
  

  
 
  
  

  
} else {
  
  

  
 
  
  

  
echo "  <font    color= red  > validation Error!    font> "; 
  
  

  
 
  
  

  
}
  
  

  
 
  
  

  
Close session to clear all registered variables
  
  

  
 
  
  

  
Session_destroy ();
  
  

  
 
  
  

  
?> 
 
 

http://www.bkjia.com/PHPjc/446325.html www.bkjia.com true http://www.bkjia.com/PHPjc/446325.html techarticle for a website, you will definitely need a page that provides validation functionality. Then we need to consider the application of the verification code in the verification page now. We're going to be here for everyone .

