Александр

if (+a + +b < 4) {
    ...
}

const createCard = ({ title, subTitle, src, poster }) => {
	const template = document.createElement('section');
	template.innerHTML = `
		<div class="card" style="width: 16rem;">
		  <a href="#theModal" class="btn btn-link"
			 data-remote="${src}"
			 data-toggle="modal" data-target="#theModal">
			 <img src="${poster}" class="card-poster" alt="image">
		  </a>
		  <div class="card-body">
			 <h3 class="card-title">${title}</h3>
			 <p class="card-text">${subTitle}</p>
		  </div>
		</div>
	`;

	return template.children[0];
};

document.body.append(createCard({
	title: 'Сказка о Царе Салтане',
	subTitle: 'Приключения отважного царевича Гвидона, прекрасной царевны-Лебедь и царя Салтана напомнят о том, что любовь, верности и сила духа всегда побеждают!',
	src: 'http://ссылка на видео',
	poster: 'img/sk-1.jpg'
}));

function func() {
  console.log(this);
}

class Some {
  constructor() {
    this.name = this.constructor.name;
  }

  method() {
    func.call(this);
  }
}

let some = new Some();
some.method(); // Some { name: 'Some' }

<form>
	<label>
		<input type="radio" name="gender" value="male">
		Мужской
	</label>
	<label>
		<input type="radio" name="gender" value="female">
		Женский
	</label>
  <button>Отправить</button>
</form>

const form = document.querySelector('form');

form.addEventListener('submit', event => {
	event.preventDefault();
  
  const data = new FormData(form);
  
  alert(data.get('gender'));
});

function get(url, callback) {
	const request = new XMLHttpRequest();

	request.addEventListener('load', function (event) {
		try {
			const data = JSON.parse(request.response);

			callback(data);
		} catch (error) {
			callback(request.response);
		}
	});

	request.open('GET', url);
	request.send();
}

get('https://jsonplaceholder.typicode.com/todos', function (data) {
	console.log(data);
});

get('URL_1', function (data_1) {
	get('URL_2', function (data_2) {
		get('URL_3', function (data_3) {
			// do something
		});
	});
});

function get(url) {
	return new Promise(function (resolve, reject) {
		const request = new XMLHttpRequest();

		request.addEventListener('load', function (event) {
			try {
				const data = JSON.parse(request.response);

				resolve(data);
			} catch (error) {
				resolve(request.response);
			}
		});

		request.addEventListener('error', function (event) {
			reject({
				status: request.status,
				text: request.statusText
			});
		});

		request.open('GET', url);
		request.send();
	});
}

Promise.all([
	get('URL_1'),
	get('URL_2'),
	get('URL_3')
]).then(function ([data_1, data_2, data_3]) {
	// do something
});

fetch('https://jsonplaceholder.typicode.com/todos')
    .then(response => response.json())
    .then(data => {
        const element = document.querySelector('pre');

        element.textContent = JSON.stringify(data, null, '\t');
    });

for (let i = 0; i < tasks.length; i++) {
    ...
    li.innerHTML = tasks[i];
    ...
}

for (let task of tasks) {
    ...
    li.innerHTML = task;
    ...
}

background-color: #292929;

color: #292929;

`some
data`

'some' + 
'data'