Graphical number verification code_PHP tutorial

Graphical Numeric Verification Code Code: ​
/*

* Filename: authpage.php

*/



srand((double)microtime( )*1000000);



//Verify whether the user input is consistent with the verification code

if(isset($_POST['authinput']))

{


if(strcmp($_POST['authnum'],$_POST['authinput'])==0)

echo "Verification successful!";

else

echo "Verification failed!";

}



//Generate a new four-digit integer verification code

while(($authnum=rand()%10000)<1000);

?>

Please enter the verification code:




>

>

-------------------------------------------------- -------------------------------------------------- ------------

/*

* Filename: authimg.php

*/
/ /Generate verification code image
Header("Content-type: image/PNG");

srand((double)microtime()*1000000);

$im = imagecreate( 58,28);

$black = ImageColorAllocate($im, 0,0,0);

$white = ImageColorAllocate($im, 255,255,255);

$ gray = ImageColorAllocate($im, 200,200,200);

imagefill($im,68,30,$gray);



//Draw the four-digit integer verification code Enter image

imagestring($im, 5, 10, 8, $HTTP_GET_VARS['authnum'], $white);



for($i=0; $i<50;$i++) //Add interference pixels

{

imagesetpixel($im, rand()%70, rand()%30, $gray);

}



ImagePNG($im);

ImageDestroy($im);

?>