check if string only contains numbers

[Bobby_S]

helloo!

Is there a function for this?
[0-9] or something.

[petitduc]

Use a regular expression with ereg :
For example, a test script :

$s = "123456";
$numbersOnly = !ereg("[^0-9]",$s);
if ($numbersOnly) {
   echo "There are only numbers in '$s' !<br/>";   

} else {
   echo "'$s' has non-numbers in it !<br/>";   

}

The regular expression "[^0-9]" matches any string that has at least one non numeric character in it (" put in front of a character set is the negation of that set).
ereg is simply a PHP wrapper for regexps.