js Dom阶段

监听与冒泡写法

      var $yeye = document.getElementById('yeye')
    $yeye.addEventListener('click', function (event) {
        alert('我是你爷爷')
    }, false)

    var $erzi = document.getElementById('erzi')
    $erzi.addEventListener('click', function (event) {   //冒泡事件
        alert('我是孙子')
    }, false)

阻止冒泡事件

    var $erzi = document.getElementById('erzi')
    $erzi.addEventListener('click', function (event) {
        event.stopImmediatePropagation()   //阻止冒泡
        alert('我是孙子')
    }, false)

阻止默认事件

   var $yes = document.getElementById('yes')
    $yes.onclick = (event) => {
        event.preventDefault()
        alert('你好,宝贝')
    }