JavaScript

Browser Events

<h2>First Method - Listening for click event on all children elements</h2>
<div id="first-parent">
</div>

<h2>Second Method - Listening for click event on the parent element</h2>
<div id="second-parent">
</div>

#first-parent, #second-parent {
  display: flex;
  justify-content: space-around;
  padding: 1rem;
  border: 3px dotted lightpink;
}

.circle {
  width: 50px;
  height: 50px;
  background-color: crimson;
  border-radius: 50%;
  box-shadow: rgba(50, 50, 93, 0.25) 0px 6px 12px -2px, rgba(0, 0, 0, 0.3) 0px 3px 7px -3px;
}

h2 {
  text-align: center;
}

// First Method - Listening on event on all children elements
let firstParentDiv = document.querySelector('#first-parent');

for(let i = 0; i < 10; i++) {
  let childDiv = document.createElement('div');
  childDiv.classList.add('circle');
  firstParentDiv.append(childDiv);
  childDiv.addEventListener("click", () => {
      childDiv.style.backgroundColor = "green";
  });
}

// Second Method - Listening on event on the parent element
let secondParentDiv = document.querySelector('#second-parent');
secondParentDiv.addEventListener("click", (e) => {
  e.target.style.backgroundColor = "green";
});

for(let i = 0; i < 10; i++) {
  let childDiv = document.createElement('div');
  childDiv.classList.add('circle');
  secondParentDiv.append(childDiv);
}

<h2>Second Method - Listening for click event on the parent element</h2>
<h3>Also ensuring that only the circles react on click</h3>
<div id="second-parent">
</div>

#second-parent {
  display: flex;
  justify-content: space-around;
  padding: 1rem;
  border: 3px dotted lightpink;
}

.circle {
  width: 50px;
  height: 50px;
  background-color: crimson;
  border-radius: 50%;
  box-shadow: rgba(50, 50, 93, 0.25) 0px 6px 12px -2px, rgba(0, 0, 0, 0.3) 0px 3px 7px -3px;
}

h2, h3 {
  text-align: center;
}

// Second Method - Listening on event on the parent element
let secondParentDiv = document.querySelector('#second-parent');
secondParentDiv.addEventListener("click", (e) => {
    if (e.target.classList.contains("circle")) {
        e.target.style.backgroundColor = "green";
    }
});

for(let i = 0; i < 10; i++) {
  let childDiv = document.createElement('div');
  childDiv.classList.add('circle');
  secondParentDiv.append(childDiv);
}