Trouble Validating Form Input

Knb15 · April 16, 2010

Hi,

I'm new to PHP, and have been searching forums to get some help with form validating and sanitizing.

I got a simple form validating code from a tutorial, and tried it just to get started.

I would like to know if i am doing anything wrong, or if perhaps there's a syntax error in the code that i could not find, because a condition in the code just does not work:

HTML Form:

<body>

<form action="example04.php" method="post" >

Enter your age: <input name="age" size="2">

<input type="submit" name="submit" value="Go">

</form>

</body>

1) PHP Code:

<?php
if (!filter_has_var(INPUT_POST, 'submit')) {
    echo "form";
    // include the form.
}

$age = filter_input(INPUT_POST, 'age', FILTER_VALIDATE_INT);
if (is_null($age)) {
    echo "The 'age' field is required.<br />";
} elseif ($age === FALSE) {
    echo "Please enter a valid age.<br />";
} else {
    echo "Welcome.<br/>";
}
?>

2) I have also tried the following:

<?php
        if(!empty($age)) //check if the age field is empty
        {
              if(is_numeric($age)) //check if user has given alphabets as age
              {
                   echo 'Welcome.';
               }
               else
               {
                     echo 'Please enter a valid age.';
                }
        }
        else
        {
              echo 'The age field is required.';
         }
?>

Script #1, when the input is null, or nothing is written, it is not returning "The age field is required." Instead it is returning "Please enter a valid age."

However, if i enter a valid age or if i enter an invalid character, the proper response is returned.

Script #2, solved the problem of the empty or null input field, however, it will not recognize when a character other than a number is type...the same response is returned for an empty input and for an input other than a number.

Probably something very minor that i'm not familiar with yet, but i appreciate it anyway!

Thanks

Knb15

ChemicalBliss · April 16, 2010

is_numeric();

Think about what this function does.

ctype_alnum();

I think this is what your looking for.

-cb-

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Trouble Validating Form Input

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