function validate_form ( )
{
    valid = true;

    if ( document.contact_form.company_name.value == "" )
    {
        alert ( "Please fill in the 'Company Name' box." );
        valid = false;
    }
	else 
	if ( document.contact_form.first_name.value == "" )
    {
        alert ( "Please fill in the 'First Name' box." );
        valid = false;
    }
	else 
	if ( document.contact_form.telephone.value == "" )
    {
        alert ( "Please fill in the 'Telephone Number' box." );
        valid = false;
    }
	else 
	if ( document.contact_form.email.value == "" )
    {
        alert ( "Please fill in the 'Email Address' box." );
        valid = false;
    }
    return valid;
}