is_string() not working as i expected

[Ugluth]

Hello I want to check that a variable the user enters is not empty and that it is a string (no numbers). Here is what i have written:

 

<?php
include('css/layout.css.php');
include('css/menu.css');
if (isset($_POST['submit'])) {
include('includes/dbconn.php');
if (is_string($_POST['name']) && strlen($_POST['name']) > 0) {
	$name = mysql_real_escape_string($_POST['name']);
} else {
	echo "Category name must be a word!<br />";
}
if (isset($name)) {
	echo $name;
} else {
	echo "something";
}
}
?>

 

and this is the form i'm getting the data from:

 

		<form action="category_add.php" method="post">
		<table class="table-view">
		  <tr>
		    <td><label for="name">Category Name</label></td>
		    <td><input type="text" name="name" id="name"></td>
		  </tr>
		  <tr>
		  	<td><input type="submit" value="Save changes" name="submit" id="submit"></td>
		  </tr>
		</table>
     </form>

 

If i enter nothing it works fine, if i enter a string it also works fine, the problem is when i enter 123 in the textbox, i dont get the "Category name must be a word!" as i expected i would. Could someone help me with this one please?

 

Thanks in advance.

[BlueSkyIS]

is_string() will not tell you whether all characters are letters. is_string() only tells you whether what you passed to it is a string. a string can include numbers. for example, this is a string: "hello 123 world";

 

If you want to tell whether there are any numbers, I would use preg_replace like this:

 

if (!empty($_POST['name'])) && strlen(preg_replace("/[\D]/","",$_POST['name'])) == 0) {
       // $_POST['name'] contains no numbers
}

[AbraCadaver]

http://us2.php.net/manual/en/function.ctype-alpha.php

 

 

[Ugluth]

Thank you very much for your replies, you cleared things up for me 

[Pikachu2000]

IIRC, all form data is sent as string type, so is_string() will return true for any form field validation.