如何使用querySelector

Question

我正在使用querySelectorAll访问index.html文件中的ID和类。我遇到的问题是我试图将数据传递到具有两个子范围的p.source类中，并且当我使用innerText或innerHTML时，尽管控制台日志显示了以下内容，但数据仍未传递到DOM中：正确传递给DOM的数据。您能否帮助我了解发生了什么以及如何将数据传递到该源类中。我是使用querySelector的新手，而MDN文档的深度并不如我所愿。下面是我的代码。

到目前为止，我已经尝试使用控制台访问childeNodes的属性，并且它们正常工作只是将数据反映在DOM中

function myQuotes() {
  var quotes = [{
      quote: "Seven billion souls that move around the sun.",
      source: "Childish Gambino",
      citation: "Feels like summer"
    },
    {
      quote: "Don't wait for your world to begin crumbling to make a change.",
      source: "Josh",
      citation: "Past midnight thoughts"
    },
    {
      quote: "The only time we will ever have is right now, no other time exist.",
      source: "Josh",
      citation: "Past midnight thoughts",
      year: 2018
    },
    {
      quote: "Every great developer you know got there by solving problems they were unqualified to solve until they actually did it.",
      source: "Patrick McKenzie",
      citation: "Twitter"

    }
  ];

  console.log('quotes', quotes);

  return quotes;
}

var myQuotesLength = myQuotes().length;
var quotes = myQuotes();

function getRandomQuote(maxNum) {
  var randomNum = Math.floor(Math.random() * maxNum);
  var randomQuote = quotes[randomNum];
  // console.log('random quote', randomQuote );
  return randomQuote;
}



function printQuote() {
  //data call to grab quotes from array of objects
  var message = getRandomQuote(myQuotesLength);
  console.log('message', message);

  //using querySelectors to dynamically pass the data from 'message' into the DOM. Each field works except for sourceField.
  var quoteField = document.querySelectorAll('.quote')[0].innerText = message.quote;
  var source_Parent = document.querySelectorAll('.source');
  console.log('parent', source_Parent);
  var sourceField = source_Parent[0].childNodes[0].innerHTML = message.source;
  console.log('source', sourceField);
  var citationField = source_Parent[0].childNodes[1].innerText = message.citation;
  var yearField = source_Parent[0].childNodes[2].innerText = message.year;
  if (yearField === undefined) {
    yearField = document.getElementsByClassName('year')[0].innerHTML = ' ';
  }
}

document.getElementById('loadQuote').addEventListener("click", printQuote, false);

body {
  background-color: #36b55c;
  color: white;
  font-family: 'Playfair Display', serif;
}

#quote-box {
  position: absolute;
  top: 20%;
  left: 10%;
  right: 10%;
  width: 80%;
  line-height: .5;
}

.quote {
  font-size: 4rem;
  font-weight: 400;
  line-height: 1.1;
  position: relative;
  margin: 0;
}

.quote:before,
.quote:after {
  font-size: 6rem;
  line-height: 2.5rem;
  position: absolute;
}

.quote:before {
  content: "“";
  top: .25em;
  left: -.5em;
}

.quote:after {
  content: "”";
  bottom: -.1em;
  margin-left: .1em;
  position: absolute;
}

.source {
  font-size: 1.25rem;
  ;
  letter-spacing: 0.05em;
  line-height: 1.1;
  text-align: right;
  margin-right: 4em;
}

.source:before {
  content: "—";
}

.citation {
  font-style: italic;
}

.citation:before {
  content: ", ";
  font-style: normal;
}

.year:before {
  content: ", ";
  font-style: normal;
}

#loadQuote {
  position: fixed;
  width: 12em;
  display: inline-block;
  left: 50%;
  margin-left: -6em;
  bottom: 150px;
  border-radius: 4px;
  border: 2px solid #fff;
  color: #fff;
  background-color: #36b55c;
  padding: 15px 0;
  transition: .5s;
}

#loadQuote:hover {
  background-color: rgba(255, 255, 255, .25);
}

#loadQuote:focus {
  outline: none;
}

@media (max-width: 420px) {
  .quote {
    font-size: 2.5rem;
  }
  .quote:before,
  .quote:after {
    font-size: 3rem;
  }
  .source {
    font-size: 1rem;
  }
}

<link href='https://fonts.googleapis.com/css?family=Playfair+Display:400,400italic,700,700italic' rel='stylesheet' type='text/css'>

<div class="container">
  <div id="quote-box">
    <p class="quote">Every great developer you know got there by solving problems they were unqualified to solve until they actually did it.</p>
    <p class="source">Patrick McKenzie<span class="citation">Twitter</span><span class="year">2016</span></p>
  </div>
  <button id="loadQuote">Show another quote</button>
</div>

最终结果是：

-我想将message.quote数据传递到quote-box id的innerHTML中（有效）

-我想将message.source数据传递到源类的innerText中（这不起作用）

-我想将message.citation数据传递到citation类的innerText中（此方法有效）

-我想将message.year数据传递到year类的innerText中（此方法有效）

Answer 1

您面对的名称是childNode，但不是.source div的childNode，而是innerText的childNode。如果您也将该名称放入<span>中，它也将成为childNode并像超级按钮一样工作。

  

这是您的“固定”代码笔，我刚刚在名称周围添加了<span>：   https://codepen.io/anon/pen/pGrBEo?editors=1010#0

或者看看这个工作示例：

function myQuotes() {
  var quotes = [{
      quote: "Seven billion souls that move around the sun.",
      source: "Childish Gambino",
      citation: "Feels like summer"
    },
    {
      quote: "Don't wait for your world to begin crumbling to make a change.",
      source: "Josh",
      citation: "Past midnight thoughts"
    },
    {
      quote: "The only time we will ever have is right now, no other time exist.",
      source: "Josh",
      citation: "Past midnight thoughts",
      year: 2018
    },
    {
      quote: "Every great developer you know got there by solving problems they were unqualified to solve until they actually did it.",
      source: "Patrick McKenzie",
      citation: "Twitter"

    }
  ];
  return quotes;
}

var myQuotesLength = myQuotes().length;
var quotes = myQuotes();

function getRandomQuote(maxNum) {
  var randomNum = Math.floor(Math.random() * maxNum);
  var randomQuote = quotes[randomNum];
  return randomQuote;
}



function printQuote() {
  var message = getRandomQuote(myQuotesLength);

  var quoteField = document.querySelectorAll('.quote')[0].innerText = message.quote;
  var source_Parent = document.querySelectorAll('.source');
  var sourceField = source_Parent[0].childNodes[0].innerHTML = message.source;
  var citationField = source_Parent[0].childNodes[1].innerText = message.citation;
  var yearField = source_Parent[0].childNodes[2].innerText = message.year;
  if (yearField === undefined) {
    yearField = document.getElementsByClassName('year')[0].innerHTML = ' ';
  }
}

document.getElementById('loadQuote').addEventListener("click", printQuote, false);

body {
  background-color: #36b55c;
  color: white;
  font-family: 'Playfair Display', serif;
}

#quote-box {
  position: absolute;
  top: 20%;
  left: 10%;
  right: 10%;
  width: 80%;
  line-height: .5;
}

.quote {
  font-size: 4rem;
  font-weight: 400;
  line-height: 1.1;
  position: relative;
  margin: 0;
}

.quote:before,
.quote:after {
  font-size: 6rem;
  line-height: 2.5rem;
  position: absolute;
}

.quote:before {
  content: "“";
  top: .25em;
  left: -.5em;
}

.quote:after {
  content: "”";
  bottom: -.1em;
  margin-left: .1em;
  position: absolute;
}

.source {
  font-size: 1.25rem;
  ;
  letter-spacing: 0.05em;
  line-height: 1.1;
  text-align: right;
  margin-right: 4em;
}

.source:before {
  content: "—";
}

.citation {
  font-style: italic;
}

.citation:before {
  content: ", ";
  font-style: normal;
}

.year:before {
  content: ", ";
  font-style: normal;
}

#loadQuote {
  position: fixed;
  width: 12em;
  display: inline-block;
  left: 50%;
  margin-left: -6em;
  bottom: 150px;
  border-radius: 4px;
  border: 2px solid #fff;
  color: #fff;
  background-color: #36b55c;
  padding: 15px 0;
  transition: .5s;
}

#loadQuote:hover {
  background-color: rgba(255, 255, 255, .25);
}

#loadQuote:focus {
  outline: none;
}

@media (max-width: 420px) {
  .quote {
    font-size: 2.5rem;
  }
  .quote:before,
  .quote:after {
    font-size: 3rem;
  }
  .source {
    font-size: 1rem;
  }
}

<link href='https://fonts.googleapis.com/css?family=Playfair+Display:400,400italic,700,700italic' rel='stylesheet' type='text/css'>

<div class="container">
  <div id="quote-box">
    <p class="quote">Every great developer you know got there by solving problems they were unqualified to solve until they actually did it.</p>
    <p class="source"><span>Patrick McKenzie</span><span class="citation">Twitter</span><span class="year">2016</span></p>
  </div>
  <button id="loadQuote">Show another quote</button>
</div>

Answer 2

问题是您正在使用childNodes，其中也包含文本。

这是MDN

的笔记

childNodes包括所有子节点，包括非元素节点，例如文本和注释节点。要获取仅元素的集合，请改用ParentNode.children。

Answer 3

您可以使用createTextNode和insertBefore方法执行此操作，例如：

const source = message.source;
const sourceNode = document.createTextNode(source);

const sourceEl = document.querySelectorAll(".source")[0];
const citationEl = document.querySelectorAll(".citation")[0];

sourceEl.insertBefore(sourceNode, citationEl);