// copyright 2009 Surge Computing Services Pty Ltd www.dealerbase.com.au www.surgewebsites.com
//

// validate supplied string follows similar format to an Australian postcode
//             i.e. 4 numeric digits
function isPostCode(query_string) {
    var numb = '0123456789';
    //if (query_string = '') return false;
    if (query_string.length = 4) {
        for (i=0;i<4;i++) {
            if (numb.indexOf(query_string.charAt(i),0)==-1) return false;
        }  
        return true;
    } else {
        return false;
    }
}