Php > Graphics

Number Verification, used to prevent form auto-completes

Number Verification, used to prevent form auto-completes

First code, the one that generates the code and checks it. Save as "numverify.php".
---
<?php
#################
# numverify.php #
#################
if (!$num_ent)
{
$nums = array("5","6","7","8","d","e","1","2","3","4","f","g","h","i","j","k","9","0","a","b","c","l","m","n","o","p","q","x","y","z","A","B","C","D","r","s","t","u","v","w","E","F","G","N","O","P","Q","R","S","H","I","J","K","L","M","T","W","X","Y","Z","U","V");
// Creates 10 random array access keys to nums.
$random_key = array_rand($nums, 10);
$random = "";
for ($i=0;$i<10;$i++)
{
// Uses random access keys to access 10 random elements in the array.
$random = $random . $nums[$random_key[$i]];
}
echo "<img src=\"pic.php?random=$random\">";
echo "<form action=\"$PHP_SELF\" method=\"post\">
Please type the code you see above. (CASE-SENSITIVE) <input type=\"text\" name=\"num_ent\"><br>
<input type=\"hidden\" name=\"random\" value=\"$random\">
<input type=\"submit\" value=\"Submit\">";
}
else
{
if ($num_ent == $random)
{
// Af they get it right ...
echo "Correct!";
}
else
{// And if they get it wrong ...
echo "Incorrect. Go back and refresh the page for a new code.";
}
}
?>
---
Second code, the one that generates image. Save as "pic.php".
---
<?php
###########
# pic.php #
###########
header("Content-type: image/png");
$im = @imagecreate(95, 18) or die("Cannot Initialize new GD image stream");
                                                 // 95,18 is the size of the image;
                                                 // height,width. Must be changed if 
                                                 // font is changed.
$background_color = imagecolorallocate($im, 225, 225, 225); // background color R,G,B
$text_color = imagecolorallocate($im, 233, 14, 91); // text color R,G,B
imagestring($im, 5, 1, 0, $random, $text_color); // "5" is the font, can be changed
                                                 // 0-1, but the size changes to the 
                                                 // dimensions must be changed. 1,0 
                                                 // is the x,y location.
imagepng($im);
imagedestroy($im);
?>