document.addEventListener("DOMContentLoaded", ()=>{
  document.getElementById("h1").addEventListener("click", (e) => {
    alert("Hello");
  }, false);
});

function dbiSize(){
	var dbi = document.querySelectorAll('p');
	if (dbi.length == 0){
		alert('p??????????????');
	}else {
		for (let i of dbi){
			i.style.fontSize = '200%';
		}
	}
}
window.addEventListener("load", function(e){
	document.body.addEventListener("click",dbiSize);
})