JSFiddle - React, Tailwind, and code Playground
by Qwerty_Wasd
JavaScript
var number = +prompt( 'Введите трехзначное число: ');
var number1 = parseInt(number / 100);
var number2 = parseInt(number / 10) % 10;
var number3 = number % 10;
if(number1===number2 || number2===number3 || number1===number3)
alert('Найдено совпадение цифр');
else
alert('Совпадений не найдено');