如何在单击操作按钮后填充变量？

<button id="myButton">点击按钮</button>

var myButton = document.getElementById("myButton");
myButton.addEventListener("click", function() {
  // 在这里执行填充变量的操作
});

var myInput = document.getElementById("myInput");
var myVariable = "Hello World";
myButton.addEventListener("click", function() {
  myInput.value = myVariable;
});

var myParagraph = document.getElementById("myParagraph");
var myVariable = "Hello World";
myButton.addEventListener("click", function() {
  myParagraph.textContent = myVariable;
});

var myVariable;
myButton.addEventListener("click", function() {
  myVariable = "Hello World";
});