Basic Form Validation Check Number? - php

Question

In this script I am checking if fields are not empty and email address is syntactically correct. How to add a text input at the bottom of my form for a basic sum question, e.g. (2+5)= I want to add a validation element to my current script to check if this equals 7.
if (empty($name) || empty($phone) || empty($email) || empty($enquiry))
{
echo " * Sorry all fields are required.";
}
elseif(!preg_match("/^[_a-z0-9-]+(\.[_a-z0-9-]+)*#[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/", $email))
{
print "<p>Sorry the email address you entered looks like it's invalid.</p>";
}
else
{
mail($to, $sub, $mes, $headers);
print "<p>Thank you ".$name." for contacting us.<br /><br />We will be in touch shortly.</p>";
}

Answer 1

If you are just wanting to validate a static sum, e.g. you know it is always going to be ( 2 + 5 ) = 7
Then you could just write a simple function to check the posted value.
// this being your posted value;
$validate = 7;
function SumCheck($value){
if ( 2 + 5 == $value ){
return true;
}
else{
return false;
}
}
Then change your initial line to;
if (empty($name) || empty($phone) || empty($email) || empty($enquiry) || !SumCheck($validate))
However, I would suggest using RECAPTCHA as Robert Podwika has suggested.

Answer 2

1 If your session is not started use in the very first line
session_start();
2 Before form is shown. Add this code. Also remember that session start must be also in file where validation is.
$numa = rand(1,5);
$numb = rand(0,4);
$_SESSION['valid_res'] = $numa+$numb;
echo "<p>To submit form please solve this equatation $numa + $numb = ?";
echo '<input type="text name="result_val" />';
3 In validation functions you should check
if(intval($_POST['resul_val']) != $_SESSION['valid_res'])
{
echo "sorry you put wrong result in validation form";
}
However, if I were you I'd use RECAPTCHA