text: function calc() {
  	let num1 = Number(document.getElementById('num1').value);
  	let num2 = Number(document.getElementById('num2').value);
  	document.getElementById('sum').value = num1 + num2;
  }
  
  function showText() {
  	document.getElementById('text').style.display = 'inline';
  	document.getElementById('more').style.display = 'none';
  }
  
  function extractText() {
  	let liArr = document.getElementsByTagName('li');
  	let res = '';
  	for (let e of liArr) {
  		res += e.textContent + '\n';
  	}
  	document.getElementById('result').textContent = res;
  }
  
  function colorize() {
  	let trArr = document.getElementsByTagName('tr');
  	for (let i = 1; i < trArr.length; i += 2) {
  		trArr[i].style.backgroundColor = 'Teal';
  	}
  }
  
  function countdown(sec) {
  	let minutes = Math.trunc(Number(sec) / 60);
  	let seconds = Math.trunc(Number(sec) % 60);
  	document.getElementById('time').value = minutes + ':' + ('0' + seconds).slice(-2);
  	setInterval(() => {
  		sec--;
  		minutes = Math.trunc(Number(sec) / 60);
  		seconds = Math.trunc(Number(sec) % 60);
  		document.getElementById('time').value = minutes + ':' + ('0' + seconds).slice(-2);
  	}, 1000);
  }
  
  function extract(id) {
  	let text = document.getElementById(id).textContent;
  	let res = [];
  	let match;
  	let pattern = /\((.+)\)/g;
  	while (match = pattern.exec(text)) {
  		res.push(match[1]);
  	}
  	return res.join('; ');
  }
  
  function sum() {
  	let tdArr = document.getElementsByTagName('td');
  	let sum = 0;
  	for (let i = 1; i < tdArr.length - 2; i += 2) {
  		sum += Number(tdArr[i].textContent);
  	}
  	tdArr[tdArr.length - 1].textContent = sum;
  }
  
  