Form Validation: Test for Numbers Only

[AndrewAK]

Here is a snippet of my code. It works fine, but checks for upper and lower case letters.

if (empty($_POST["lastname"])) {
            $lastnameErr = "Lastname is required";
        } else {
            $lastname = test_input($_POST["lastname"]);
            if (!preg_match("/^[a-zA-Z ]*$/",$lastname)) {
                $lastnameErr = "Only letters and white space allowed";
                }
    }

I need this to check for numbers only IE: 0-9 for a phone number format.

Thank you

[Gabrielphp]

You can use a php function called is_numeric().

if(is_numeric($var)) { //do stuff } else { //do other stuff }

Hope this is what you want.

[AndrewAK]

Thank you Gabrielphp, that worked perfectly. I tested for the negative.

if(!is_numeric($phonenum1)){ $phonenum1Err="Only numbers0-9"}