var mac = (navigator.userAgent.indexOf("Mac") != -1);

function validate_form ( )
{
	valid = true;

        if ( document.contact_form.FirstName.value == "" )
        {
                alert ( "Please fill in the 'Your Name' box." );
                valid = false;
                return valid;
        }
        else if (document.contact_form.Email.value == "" )
        {
                alert ( "Please fill in the 'Your Email Address' box." );
                valid = false;
        }
       
         return valid;
}