// áèáëèîòåêà äëÿ ïðîâåðêè äàííûõ ââîäèìûõ ïîëüçîâàòåëåì â ïîëÿ ôîðìû

var check_digits = '0123456789';
var check_en_letters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
var check_ru_letters = 'àáâãäå¸æçèéêëìíîïðñòóôõö÷øùüûúýþÿÀÁÂÃÄŨÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÜÛÚÝÞß';

// ïðîâåðêà íà ïóñòîòó ïîëÿ (òî÷íåå òåêñòîâîé ñòðîêè)
function check_empty(str) {
	var space_sym = ' \t\r\n\f';
	var i;
	if( (str == null) || (str == '') || (str.length == 0) ) return true;
	for(i = 0; i < str.length; i++)
		if(space_sym.indexOf(str.charAt(i)) == -1) return false;
	return true;
}

// îãðàíè÷åíèå ââîäà ïîëüçîâàòåëÿ òîëüêî îïðåäåëåííûìè ñèìâîëàìè
function check_restrict_syms(event,syms) {
	var key;
	var key_char;
	var i;

	if(window.event) key = window.event.keyCode;
	else if(event) key = event.which;
	else return true;

	// âîçâðàò êàðåòêè è ò.ï.
	if( (key == null) || (key == 0) || (key == 8) || (key == 13) || (key == 27) ) return true;

	key_char = String.fromCharCode(key);

	if(syms.indexOf(key_char) == -1) return false;
		else return true;
}