js:addEventListener与onclick同时使用

<button id="btn">点击</button>

<script>
document.getElementById("btn").addEventListener('click', function (e) {
  console.log("点击了button1");
})

document.getElementById("btn").addEventListener('click', function (e) {
  console.log("点击了button2");
})

document.getElementById("btn").onclick = function (e) {
  console.log("点击了button3");
}

document.getElementById("btn").onclick = function (e) {
  console.log("点击了button4");
}
</script>

点击按钮后输出如下

点击了button1
点击了button2
点击了button4