Lets now move on to variable types.  In other words, check the variable content to find if it is numeric or string type.  For example:

    <form>
    <INPUT name=somevar type=radio value=1>
    <INPUT name=somevar type=radio value=2>
    </form>
    
    The somevar variable is numeric. And if you have:
    
    <form>
    <INPUT name=somevar type=radio value="1">
    <INPUT name=somevar type=radio value="2">
    </form>

The somevar variable is a string.  Please note the importance of quotes.

You can check whatever is a string or an integer using is_integer(value) function that returns true if value is an integer.  For example:

    If (!is_integer($somevar)){
    echo (" Hacking Attempt ");
    exit;
    }

It is quite common to assign small integer values to your variables in a form. In this case, it is useful to check if your variable is an integer or a string. However, please notice that all variables sent using GET method are strings unlike variables sent using POST method that can be either strings or integers.


http://www.devshed.com/c/a/PHP...riables/2/