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P粉2540777472023-09-06 11:09:33
// 缓存经常访问的元素 const headerElement = document.getElementById("header"); const redButton = document.getElementById("redButton"); const greenButton = document.getElementById("greenButton"); // 为整个文档添加事件监听器,利用事件委托 document.addEventListener("click", function(event) { const targetId = event.target.id; if (targetId === "redButton") { headerElement.innerHTML = "Red"; headerElement.style.color = "red"; redButton.classList.add("active-red"); greenButton.classList.remove("active"); } else if (targetId === "greenButton") { headerElement.innerHTML = "Green"; headerElement.style.color = "green"; greenButton.classList.add("active-green"); redButton.classList.remove("active"); } });
.active { color: white; } .active-red { color: white; background-color: red; } .active-green { color: black; background-color: grey; }
<h1 id="header">Red Or Green</h1> <button id="redButton">Red</button> <button id="greenButton">Green</button>