function getID(id) { return document.getElementById(id); }
function check_regex(n,v){return RegExp (n).test(v)}
function check_integer(n){return RegExp ( /^\d+$/ig ).test(n)}
function check_string(s){return RegExp ( "^[a-zA-Z]+$" ).test(s)}
function check_alfanum_string(s){return RegExp ( "^[a-zA-Z0-9]+$" ).test(s)}
function check_date(s){return RegExp ( "[0-9]{2,2}.[0-9]{2,2}.[0-9]{4,4}$" ).test(s)}
function check_time(s){return RegExp ( "^[012][0-9]:[0-5][0-9]$" ).test(s)}
function check_email(s){return RegExp ( "^[a-zA-Z0-9-_.]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,4}$" ).test(s)}
function check_url(s){var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/; return regexp.test(s)}
function check_sqldate(s){reg_date = /^\d{4}-\d{2}-\d{2}$/; return reg_date.test(s)}
function check_hex(n) {return (n<16 ? '0' : '' ) + n.toString(16)}