Question

I’m trying to use a foreach loop to search for word in $_POST, but it doesn’t work? Help is preciated.

$unsafeWords = array('content-typ','bcc','cc');
foreach ($_POST as $key => $input) {
    foreach ($unsafeWords as $value) {
        $_POST = str_ireplace($value, "", $input) ;
    }
}

Answer 1

Don’t overwrite the $_POST array with a string

$unsafeWords = array('content-typ','bcc','cc');
foreach ($_POST as $key => $input) {
    foreach ($unsafeWords as $value) {
        $_POST[$key] = str_ireplace($value, "", $input) ;
    }
}

though I dislike overwriting the original $_POST array and would prefer to build a new array of cleaned values

Note that you don’t need to loop the $unsafeWords array, but can pass an it as an array directly to str_ireplace()

EDIT

Example of using the $unsafeWords array as an argument for str_ireplace() rather than looping through it with foreach() and calling str_ireplace() for each entry.

$unsafeWords = array('content-type','bcc','cc');
foreach ($_POST as $key => $input) {
    $_POST[$key] = str_ireplace($unsafeWords, "", $input) ;
}

and you’re not replacing with a space, you’re replacing with an empty string (effectively removing the unsafe strings from your $_POST vars)

EDIT 2

I guess it’s OK to put this inside the
foreach loop as well?

Not quite… if you’re just adding it as an extra line within the loop, you’ll overwrite your previous substitutions.
Do it as:

$unsafeWords = array('content-type','bcc','cc');
foreach ($_POST as $key => $input) {
    $_POST[$key] = str_ireplace($unsafeWords, "", filter_var($input, FILTER_SANITIZE_STRIPPED)) ;
}