如何使用 javascript 将默认输出文本设置为从下拉菜单中选择的选项

Question

我正在为我的网站创建一个自定义字体预览框（我是一名字体设计师，希望我的客户能够在购买前试用字体）并且我已经使用尽可能简单的方式将其全部编码javascript、css 和 html。一切正常，但我遇到了一个问题。

盒子的工作原理如下：

顶部有一个带有占位符文本的文本区域，其中客户可以输入自己的文字
select 有一个字体下拉菜单（其中之一是 "selected" 通过 html) 和一个文本框来更改字体大小
然后在这些下面，有一行输出显示占位符或客户键入的文本。

我遇到的问题是我希望输出从一开始就以 "selected" 字体显示，而是以网站的默认字体显示。它不会更改为 selected 字体，直到我在下拉菜单中取消 select 并重新 select 该字体。

我可以使用标签在 html 中进行设置，但这只会影响占位符文本。如果客户在框中键入任何内容，它会立即变回默认字体，并且客户必须取消 select 并重新 select 下拉列表中的字体才能更改输出。所以这很令人困惑。

这是 JSBin link：https://jsbin.com/lenutufibu/2/edit?html,css,js,output

这是我使用的代码：

<h2>Test-Drive This Font</h2>
<div class="fontForm">
<form method="POST">

    <textarea name="customText" placeholder="Type your own text here and it will preview below." id="customText" cols="80" rows="1"></textarea>


  <div class="font-third">
    Font Size  
    <br>
    <input type="text" placeholder="24" id="customSize">
  </div>
  <div class="font-third">
    Select Font <select name="customFont" id="customFont">
      <option value="flatline-regular" id="flatline-regular" selected>Flatline Regular</option>
      <option value="arial" id="arial">Arial</option>
    </select>
  </div>
</form>

敏捷的棕色狐狸跳过懒惰的狗。

然后 CSS 仅用于我示例中使用的字体：

@font-face {   
font-family: 'flatline-regular';   
src: url(https://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be111ff9ed15ac0b5f31/1578417681898/Flatline-Regular.otf), url(fontURL.woffhttps://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be2a1ff9ed15ac0b6230/1578417707009/flatline-regular-webfont.woff), url(fontURL.woff2https://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be31e375184c7b041567/1578417713132/flatline-regular-webfont.woff2); 
}

和javascript（使用https://code.jquery.com/jquery-3.1.0.js）：

  $(document).ready(() => {

  $('#customText').on('keyup', event => {
    $('.font-preview').html($(event.currentTarget).val());
  });

  $('#customFont').on('change', event => {
    $('.font-preview').css('fontFamily', $(event.currentTarget).val());
  });

  $('#customSize').on('keyup', event => {
    var fontSize = ($(event.currentTarget).val()) + 'px';
    $('.font-preview').css('fontSize', fontSize);
  });

})

Answer 1

您只需要在 DOM 就绪事件中设置所选字体，可以像这样完成：

$('.font-preview').css('fontFamily', $("#customFont").val());

查看下面的工作代码

$(document).ready(() => {
  $('.font-preview').css('fontFamily', $("#customFont").val());
  $('#customText').on('keyup', event => {
    $('.font-preview').html($(event.currentTarget).val());
  });

  $('#customFont').on('change', event => {
    $('.font-preview').css('fontFamily', $(event.currentTarget).val());
  });

  $('#customSize').on('keyup', event => {
    var fontSize = ($(event.currentTarget).val()) + 'px';
    $('.font-preview').css('fontSize', fontSize);
  });
})

@font-face {
  font-family: 'flatline-regular';
  src: url(https://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be111ff9ed15ac0b5f31/1578417681898/Flatline-Regular.otf), url(fontURL.woffhttps://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be2a1ff9ed15ac0b6230/1578417707009/flatline-regular-webfont.woff), url(fontURL.woff2https://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be31e375184c7b041567/1578417713132/flatline-regular-webfont.woff2);
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="font-box-container">

  <h2>Test-Drive This Font</h2>
  <div class="fontForm">
    <form method="POST">

      <textarea name="customText" placeholder="Type your own text here and it will preview below." id="customText" cols="80" rows="1"></textarea>


      <div class="font-third">
        Font Size
        <br>
        <input type="text" placeholder="24" id="customSize">
      </div>
      <div class="font-third">
        Select Font
        <select name="customFont" id="customFont">
          <option value="flatline-regular" id="flatline-regular" selected>Flatline Regular</option>
          <option value="arial" id="arial">Arial</option>
        </select>
      </div>
    </form>
  </div>
  <div class="font-preview">The quick brown fox jumps over the lazy dog.</div>

</div>

Answer 2

在 $(document).ready(() => { 下方添加 $('.font-preview').css('fontFamily', $('#customFont').val());。

像这样：

  $(document).ready(() => {
    $('.font-preview').css('fontFamily', $('#customFont').val());
    
  $('#customText').on('keyup', event => {
    $('.font-preview').html($(event.currentTarget).val());
  });
  
  $('#customFont').on('change', event => {
    $('.font-preview').css('fontFamily', $(event.currentTarget).val());
  });
  
  $('#customSize').on('keyup', event => {
    var fontSize = ($(event.currentTarget).val()) + 'px';
    $('.font-preview').css('fontSize', fontSize);
  });
  
})

@font-face {   
font-family: 'flatline-regular';   
src: url(https://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be111ff9ed15ac0b5f31/1578417681898/Flatline-Regular.otf), url(fontURL.woffhttps://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be2a1ff9ed15ac0b6230/1578417707009/flatline-regular-webfont.woff), url(fontURL.woff2https://static1.squarespace.com/static/5579e750e4b06072e5c3004a/t/5e14be31e375184c7b041567/1578417713132/flatline-regular-webfont.woff2); 
}

<!DOCTYPE html>
<html>
<head>
<meta name="description" content="custom-font-previewer">
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
<script src="https://code.jquery.com/jquery-3.1.0.js"></script>
  
</head>
<body>

  <div class = "font-box-container">

    <h2>Test-Drive This Font</h2>
    <div class="fontForm">
    <form method="POST">

        <textarea name="customText" placeholder="Type your own text here and it will preview below." id="customText" cols="80" rows="1"></textarea>
      
      
      <div class="font-third">
        Font Size  
        <br>
        <input type="text" placeholder="24" id="customSize">
      </div>
      <div class="font-third">
        Select Font <select name="customFont" id="customFont">
          <option value="flatline-regular" id="flatline-regular" selected>Flatline Regular</option>
          <option value="arial" id="arial">Arial</option>
        </select>
      </div>
    </form>
  </div>
    <div class="font-preview">The quick brown fox jumps over the lazy dog.</div>

  </div>
  
</body>
</html>

如何使用 javascript 将默认输出文本设置为从下拉菜单中选择的选项

How to set default output text to selected option from dropdown menu using javascript

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