Restricting an input field to only numbers with preg_match_all() (PHP)
This is a pretty easy way to restrict a field to only numbers.
The \D in the preg match is short for [^0-9], which will match all characters, except 0-9.
I’m new to the regex, so there might be a better way to do this. But this works for me.
I like to do all the validating on the server side, just in case someone has javascript disabled.
<?php
if(isset($_POST['submit'])) {
preg_match_all("/\D/i", $_POST['number'], $matches);
if(!$matches[0][0]) {
print("Your right " . $_POST['number'] . " is a number!");
exit;
}
else {
print("That is not a number!");
exit;
}
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Preg Match All</title>
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<meta name="generator" content="Geany 0.18svn" />
</head>
<body>
<form id="preg_match_all" name="preg_match_all" method="post" action="<?php $_SERVER['PHP_SELF']; ?>">
Enter a Number : <input type="text" name="number" />
<input type="submit" value="submit" name="submit" />
</form>
</body>
</html>
Leave a Reply
You must be logged in to post a comment.