//******************************************************************************************* ISEMAIL
function isEmail(email) {
  var cnt = 1;
  var isEmail = 1;
  var povolstr = 'abcdefghijklmnopqrstuvwxyz0123456789@.-_';

  // test na spatne znaky
  for (cnt=1;cnt<=email.length;cnt++) {
    var email_cast = email.substring(cnt, cnt+1);
    if(povolstr.indexOf(email_cast)<0) {isEmail = 0}
  }
  if(email.lenght<6) {isEmail = 0}  //malo znaku
  if(email.indexOf('@')<3 || email.indexOf('@')>email.length-6) {isEmail = 0} //@ je alespon 3 a alespon 5 od konce
  if(email.indexOf('@')>email.lastindexOf('.')) {isEmail = 0} //@ je za teckou
  if(email.indexOf('.')+3> email.length) {isEmail = 0} // za teckou je malo znaku

  return isEmail;
}

//******************************************************************************************* COUNTDOWN
var js_countdown = function () {
	var time_left = 10; //number of seconds for countdown
	var output_type = 'HMS'; //co zobrazit
	var output_element_id = 'js_countdown_time';
	var keep_counting = 1;
	var no_time_left_message = 'Čas vypršel';
	var full_output = '';
 
	function countdown() {
		if(time_left < 2) {
			keep_counting = 0;
		}
		time_left = time_left - 1;
	}
 	function add_leading_zero(n) {
		if(n.toString().length < 2) {
			return '0' + n;
		} else {
			return n;
		}
	}
	function format_output() {
		var hours, minutes, seconds;
		full_output = '';

		if(output_type.indexOf('H')>=0) {
			hours = Math.floor(time_left / 3600);
			hours = add_leading_zero( hours );
			full_output=full_output+hours+':';
		}
		if(output_type.indexOf('M')>=0) {
			minutes = Math.floor(time_left / 60) % 60;
			minutes = add_leading_zero( minutes );
			full_output=full_output+minutes+':';
		}
		if(output_type.indexOf('S')>=0) {
			seconds = time_left % 60;
			seconds = add_leading_zero( seconds );
			full_output=full_output+seconds;
		}
		return full_output;
	}
	function show_time_left() {
		document.getElementById(output_element_id).innerHTML = format_output();//time_left;
	}
	function no_time_left() {
		document.getElementById(output_element_id).innerHTML = no_time_left_message;
	}
	return {
		count: function () {
			countdown();
			show_time_left();
		},
		timer: function () {
			js_countdown.count();
 
			if(keep_counting) {
				setTimeout("js_countdown.timer();", 1000);
			} else {
				no_time_left();
			}
		},
		//Kristian Messer requested recalculation of time that is left
		setTimeLeft: function (t) {
			time_left = t;
			if(keep_counting == 0) {
				js_countdown.timer();
			}
		},
		init: function (t, element_id, type) {
			time_left = t;
			output_type = type;
			output_element_id = element_id;
			js_countdown.timer();
		}
	};
}();