//switch: sizes//////////////////////////////////////////////////////
let size = prompt('enter ukr size', "");
switch (size) {
   case "40":
      alert('us size = 6(S)');
      break
   case "42":
      alert('us size = 8(M)');
      break
   case "44":
      alert('us size = 10');
      break
   case "46":
      alert('us size = 12(L)');
      break
   case "48":
      alert('us size = 14');
      break
   case "50":
      alert('us size = 16(XL)');
      break
   case "52":
      alert('us size = 18');
      break
   case "54":
      alert('us size = 20(XXL)');

}


//switch: if//////////////////////////////////////////////////////
let color = prompt("Введите цвет");
if (color === "red") {
   document.write("<div style='background-color: red;'>красный</div>")
}

else if (color === "black") {
   document.write("<div style='background-color: black; color: white;'>черный</div>");
}
else if (color === "blue") {
   document.write("<div style='background-color: blue;'>синий</div>");
}
else if (color === "green") {
   document.write("<div style='background-color: green;'>зеленый</div>");
}
else {
   document.write("<div style='background-color: gray;'>Я не понял</div>");
}


//prompt: or//////////////////////////////////////////////////////
let age = prompt('Сколько тебе лет?');
if (age > 0) { alert(`Ты ${2022 - age} года рождения!`) }
else if (age === "0" || age === "") { alert('ошибка') }


//confirm: or this days///////////////////////////////////////////
let question = confirm('шоппинг?') ? alert('летс-гоу!!!') : alert('ты-бяка');


//confirm: if this days///////////////////////////////////////////
let question1 = confirm('шоппинг?');
if (question1 === true) { alert('летс-гоу!!!') }
else if (question1 === false) { alert('ты-бяка') }


//triple prompt///////////////////////////////////////////////////
let firstname = prompt("ваше имя?");
let lastname = prompt("ваше фамилия?")
let patronymic = prompt("ваше отчество?")
alert(firstname + " " + lastname + " " + patronymic)


//default: or/////////////////////////////////////////////////////
const default1 = "иван"
const default2 = "иванов"
const default3 = "иванович"
let firstname1 = prompt("ваше имя?") || default1;
let lastname1 = prompt("ваше фамилия?") || default2;
let patronymic1 = prompt("ваше отчество?") || default3;
alert(firstname1 + " " + lastname1 + " " + patronymic1)


//default: if/////////////////////////////////////////////////////
const default1 = "иван"
const default2 = "иванов"
const default3 = "иванович";
let firstname = prompt("ваше имя?")
if (firstname === true) { firstname }
else if (firstname === "" || firstname === null) { firstname = default1 };
let lastname = prompt("ваше фамилия?")
if (lastname === true) { lastname }
else if (lastname === "" || lastname === null) { lastname = default2 };
let patronymic = prompt("ваше отчество?")
if (patronymic === true) { patronymic }
else if (patronymic === "" || patronymic === null) { patronymic = default3 };
alert(firstname + " " + lastname + " " + patronymic)



//login and password//////////////////////////////////////////////
let login = prompt('введите логин');
if (login === "admin") { alert("ok.введите пароль.") }
else if (login !== "admin") { alert("неверный логин!") }
let password = prompt('введите пароль');
if (login === "admin" && password === "qwerty") { alert("вы успешно ввели логин и пароль!") }
else if (password === "qwerty") { alert("вы успешно ввели пароль!") }
else if (password !== "qwerty") { alert("неверный пароль!") }