Run results for: Event Bubbling and Event Capturing

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser: Chrome 134

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Delegation	2138.0 Ops/sec
Targetting	350.9 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

const buttons = Array.from({length: 10000}, () => document.createElement('button'))
const events = new Map()

const addListener = (event, target, listener) => {
  let targets = events.get(event)
  if (targets === undefined) {
    targets = new Map()
    events.set(event, targets)
  }

  let listeners = targets.get(target)
  if (listeners === undefined) {
    listeners = new Set()
    targets.set(target, listeners)
  }

  listeners.add(listener)
}

Tests:

Delegation
buttons.forEach((target) => { addListener('click', target, console.log) addListener('focus', target, console.log) addListener('blur', target, console.log) })
Targetting
buttons.forEach((button) => { button.addEventListener('click', console.log) button.addEventListener('focus', console.log) button.addEventListener('blur', console.log) })

Run results for: Event Bubbling and Event Capturing

Delegation

Targetting