function validate_form(emailform){

        var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/		

        if ( document.emailform.firstname.value == "" ){
                alert ( "Please fill in your first name." );
                return false;
        }

        if ( document.emailform.lastname.value == "" ){
                alert ( "Please fill in your last name." );
                return false;
        }

	if (!filter.test(document.emailform.email.value)) {
		alert('Please enter a valid email address.');
		return false;
	}
        
        if ( document.emailform.organization.value == "" ){
                alert ( "Please fill in your organization or school." );
                return false;
        }

        if ( document.emailform.state.value == "" ){
                alert ( "Please fill in your state." );
                return false;
        }
        
         if ( document.emailform.country.value == "" ){
                alert ( "Please fill in your country." );
                return false;
        }

}