PHP检查字符串之前或之后是否有多个空格

Question

On my website, after a user registers they can change their username at any time. The minimum amount of characters is 6 and max amount is 25.

Here's some of the coding to check the length and remove characters:

$users_new_name = strip_tags($_POST['new_name']);
$new_name = preg_replace("/[^0-9a-zA-Z -]/", "", $users_new_name);
// Check Length
if (ctype_space($new_name)) {
$message = die('<span class="Fail">Error: Name Must Be At least 6 Characters Long!</i></span>');    
}
if(strlen($new_name) < 6) {
$message = die('<span class="Fail">Error: Name Must Be At least 6 Characters Long!</i></span>');
}
if(strlen($new_name) > 25) {
$message = die('<span class="Fail">Error: Name Can\'t Be More Than 25 Characters Long!</i></span>');
}

The issue I'm having is if you type in 5 spaces and then a letter or number, There new name will be that letter or number; Or if you type in a letter or number then 5 spaces. How could I prevent this from happening?

Here's a screenshot of the example

Answer 1

I do not understand why tags would be in a POST.

Spaces becomes a non-issue if you change:

$users_new_name = strip_tags($_POST['new_name']);

To

$users_new_name = trim(strip_tags($_POST['new_name']));

Or ideally (strip tags is unnecessary):

$users_new_name = trim($_POST['new_name']);

Change the RegEx expression to /[^0-9a-zA-Z]/ to eliminate spaces and dashes.