when to use queryselector code example

Example 1: queryselector

var el = document.querySelector(".myclass");

Example 2: javascript queryselector

//Pretend there is a <p> with class "example"
const myParagraph = document.querySelector('.example');
//You can do many this with is
myParagraph.textContent = 'This is my new text';

Example 3: dom queryselector

// TO select all the h1 from Html
document.querySelectorAll("h1")

//To select h1 from a particular class or id
document.querySelector(".className/#id h1")