javascript - 如何更改javascript dom中访问过的 anchor 链接的颜色

Question

我在 Dom 中遇到了问题。我想根据 alreadyRead ( bool 值)更改访问链接的颜色。我是这个领域的新手，所以如果我做错了什么，请原谅我。这是我的代码片段。提前致谢!

var books = [
  {
    title: 'The Design of EveryDay Things',
    author: 'Don Norman',
    alreadyRead: false
  },
  {
    title: 'The Most Human Human',
    author: 'Brian Christian',
    alreadyRead: true
  }
];

var appHandle = document.getElementById('app');
var ulTag = document.createElement('ul')
books.forEach(book =>{
  if(book.alreadyRead === true){
    document.linkcolor="green"
  } else{
    document.linkcolor ="red"
  }
  var liTag = document.createElement('li');
  var navList =document.createTextNode(`${book.title} by ${ book.author}`)
  var aTag = document.createElement('a')
  aTag.setAttribute('href','#');
  aTag.appendChild(navList)
  liTag.appendChild(aTag);
  ulTag.appendChild(liTag);
})
appHandle.appendChild(ulTag)

Answer 1

最简单的是，您可以通过以下行实现您想要的效果:

aTag.classList.toggle('alreadyRead', book.alreadyRead);

此行使用 Element.classList API 根据开关切换相关 aTag 元素节点上的 alreadyRead 类名称跟在类名后面。如果开关返回true，则添加类(如果尚不存在)，或者如果开关返回false，则删除类名(如果存在)。

var books = [{
    title: 'The Design of EveryDay Things',
    author: 'Don Norman',
    alreadyRead: false
  },

  {
    title: 'The Most Human Human',
    author: 'Brian Christian',
    alreadyRead: true

  }
];

var appHandle = document.getElementById('app');
var ulTag = document.createElement('ul')
books.forEach(book => {
  var liTag = document.createElement('li');
  var navList = document.createTextNode(`${book.title} by ${ book.author}`);
  var aTag = document.createElement('a')
  aTag.setAttribute('href', '#');
  aTag.appendChild(navList)
  liTag.appendChild(aTag);
  ulTag.appendChild(liTag);
  
  aTag.classList.toggle('alreadyRead', book.alreadyRead);
})
appHandle.appendChild(ulTag)

.alreadyRead {
  color: limegreen;
}

<div id="app"></div>

JS Fiddle demo .

引用文献:

• Element.classList .