Validation - Checking For Blank Spaces

I want to check for blank spaces in an input box. Here is the code I'm working with but I'm not sure of the correct syntax:

<?
if ($Location == " ")
{
echo "<p>The filename contains invalid characters (blank spaces)</p>";
die;}
?>

I think I need to replace == (equals) with contains.. but I don't know the syntax for that.

Thanks for any advice.

You probably want to use regular expressions:

if (ereg ("[[:space:]]", $Location)) {
&nbsp;&nbsp;&nbsp;die ( ... );
}