I'm trying to do some form validation in php using preg_match. This is what I would like to allow:

Any letters from a-z, regardless of case
can include the characters . - ' ,
can include spaces
all of the above should be allowed to be in any order throughout the string.

I do not want it to include numbers, semi-colons, colons, hash (pound sign), back or forward slashes, brackets (either curly or square), dollar signs, greater than or less than signs, or other characters such as that.

I have written:

Code:if (!preg_match("%[a-zA-Z\.\,\-\'\ ]%",$field_name))
{
invalid output would go here
exit;
}


It must be wrong because I am allowed to enter things like ...
O'Sm#ith
Smith 1
Smith1

I haven't the foggiest I idea how to correct my problem. I've had a look at some regexp sites to try to debug my syntax, but that this point I'm lost. Can anyone give me some hints?

Cheers
Heiko

I think this expression should do it:

/^([a-zA-Z]|[\'\,\.\-\s])*$

PHP Code:

$field_name = array('O\'Sm#ith', 'Smith 1', 'Smith1', 'Smith', 'O\'Smith', 'Sm-ith');

foreach($field_name as $field)
{
    echo (int) preg_match("/^([a-zA-Z]|[\'\,\.\-\s])*$/", $field);
}

//output: 000111 


I never was particularly good with regular expressions so there is a good chance someone will come along with a better solution.