如何用JavaScript实现点击模态框外部关闭多模态框

我在网站设计中需要在一个页面内创建多个模态框，已完成模态框制作，希望实现点击模态框外部时关闭该模态框的功能。但使用window.onclick = function(event){...}这段代码时，仅对最后一个模态框（第3个）生效，其余两个模态框（第1、2个）完全无效，不清楚代码哪里存在问题，恳请指导。

原始代码 #

HTML #

<button class="trigger">Modal 1</button>
<button class="trigger">Modal 2</button>
<button class="trigger">Modal 3</button>

<div class="modal">
    <div class="modal-content">
        <span class="btn-close">&times;</span>
        <h1>modal 1</h1>
    </div>
</div>

<div class="modal">
    <div class="modal-content">
        <span class="btn-close">&times;</span>
        <h1>modal 2</h1>
    </div>
</div>

<div class="modal">
    <div class="modal-content">
        <span class="btn-close">&times;</span>
        <h1>modal 3</h1>
    </div>
</div>

CSS #

.modal {
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    opacity: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    visibility: hidden;
    transform: scale(1.1);
    transition: visibility 0s linear 0.25s, opacity 0.25s 0s, transform 0.25s;
}

.modal-content {
    align-self: center;
    background-color: white;
    padding: 1rem 1.5rem;
    width: 24rem;
    border-radius: 0.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.btn-close {
    float: right;
    width: 1.5rem;
    line-height: 1.5rem;
    text-align: center;
    cursor: pointer;
    border-radius: 0.25rem;
    background-color: lightgray;
}

.show-modal {
    opacity: 1;
    visibility: visible;
    transform: scale(1);
    transition: visibility 0s linear 0s, opacity 0.25s 0s, transform 0.25s;
}

JavaScript #

const triggers = document.getElementsByClassName("trigger");
const triggerArray = Array.from(triggers).entries();
const modals = document.getElementsByClassName("modal");
const closeButtons = document.getElementsByClassName("btn-close");

for (let [index, trigger] of triggerArray) {
  const toggleModal = () => {
    modals[index].classList.toggle("show-modal");
  };
  trigger.addEventListener("click", toggleModal);
  closeButtons[index].addEventListener("click", toggleModal);
  
  // 以下两种写法仅最后一个模态框生效
  // window.onclick = function(event) {
  //     const isClickInside = modals[index].contains(event.target);
  //     if (!isClickInside) {
  //         modals[index].classList.toggle("show-modal");
  //     }
  // };

  // window.onclick = function(event) {
  //     if (event.target === modals[index]) {
  //         modals[index].classList.toggle("show-modal");
  //     }
  // };
 
  // 此写法正常工作
  window.addEventListener('click', function(event){
    if(event.target === modals[index]){
      modals[index].classList.remove("show-modal");
      console.log(modals[index])
    }          
  });
}

问题原因 #

1. 事件覆盖问题：使用window.onclick = ...赋值事件处理函数时，每次循环都会覆盖之前绑定的函数，最终只有最后一次循环中的函数会生效，因此仅最后一个模态框的逻辑能触发。
2. toggle的潜在问题：之前的代码用toggle切换模态框状态，若模态框已关闭时点击外部，会意外打开模态框；改用remove则只会执行关闭操作，逻辑更稳妥。

优化后的代码 #

const triggers = document.getElementsByClassName("trigger");
const modals = document.getElementsByClassName("modal");
const closeButtons = document.getElementsByClassName("btn-close");

for (let index = 0; index < triggers.length; index++) {
  const modal = modals[index];
  const toggleModal = () => {
    modal.classList.toggle("show-modal");
  };

  // 绑定触发器和关闭按钮的切换事件
  triggers[index].addEventListener("click", toggleModal);
  closeButtons[index].addEventListener("click", toggleModal);

  // 点击模态框背景（外部）时关闭
  window.addEventListener('click', function(event){
    if(event.target === modal){
      modal.classList.remove("show-modal");
    }          
  });
}

优化说明 #

• 改用普通for循环，逻辑更直观，无需转换为entries数组
• 将当前循环的模态框存为变量modal，代码可读性更强
• 保留addEventListener的绑定方式，确保所有模态框的监听都能生效
• 继续使用remove替代toggle，避免误操作打开模态框

内容的提问来源于stack exchange，提问作者h.m.p.frontendDeveloper