let txt4 = document.createElement('h2');
txt4.innerHTML = 'Text4';
document.body.append(txt4);
console.log(document.getElementById('t1').innerText);
console.log(document.querySelectorAll('div')[1].innerHTML);
console.log(document.querySelector('div.t3').innerHTML);
<body> <h2>Hello World</h2> <hr> <div id="t1"> 1. Text1 </div> <div id="t2"> 2. Text2 </div> <div class="t3"> 3. Text3 </div> </body>