javascript - <textarea> 的灵活高度作为新的换行符

Question

我以前从未见过这种做法，但我希望它可以做到。我正在尝试在其中写入文本时自动设置文本区域的高度。如此处所见...

http://i.stack.imgur.com/oxRfj.jpg

http://i.stack.imgur.com/XVzYT.jpg

希望这些图片能解释我的意思。第二张图片也显示了它的理论最大高度。

https://jsfiddle.net/nupk26Ly/

.text-f {
border: none;
border-bottom: #183A4C solid 1px;
color: #183A4C;
font: 1rem/2.4rem Georgia, serif;
margin-top: 40px;
resize: none;
height: 40px;
width: 100%;
}

Answer 1

这是一个使用 jquery 的解决方案。希望对您有所帮助。

function h(e) {
  $(e).css({'height':'40','overflow-y':'hidden'}).height(e.scrollHeight);
}
$('textarea').each(function () {
  h(this);
}).on('input', function () {
  h(this);
});

.text-f {
    border: none;
    border-bottom: #183A4C solid 1px;
    color: #183A4C;
    font: 1rem/2.4rem Georgia, serif;
  margin-top: 40px;
    height: 40px;
    width: 100%;
}

.form-btn {
    background: #183A4C;
    border: solid 1px #183A4C;
    color: #fff;
    cursor: pointer;
    display: block;
    font: 1rem/1.333rem Georgia, serif;
    height: 30px;
    width: 140px;
    margin: 10px 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<textarea name="Message" class="text-f" placeholder="Describe your project..."></textarea>

<button class="form-btn" type="button">Submit</button>

纯Javascript解决方案(PS:我在textarea标签中添加了一个ID(textarea))

var textarea = document.getElementById("textarea");

textarea.oninput = function() {
  textarea.style.height = "";
  /* textarea.style.height = Math.min(textarea.scrollHeight, 300) + "px"; */
textarea.style.height = textarea.scrollHeight + "px"
};

.text-f {
  border: none;
  border-bottom: #183A4C solid 1px;
  color: #183A4C;
  font: 1rem/2.4rem Georgia, serif;
  width: 100%;
  resize: none;
  height: 40px;
}

<div id="content">
  <div id="main-headline">
    <h1 class="main-header">Fill out the form or contact me alternatively.</h1>
  </div>

  <!----- content ------>
  <div class="content-container">
   <!----- row 1 ------>
    <section class="row">
      <!----- form ------>
      <form name="contact-f" action="#" method="post">
        <div class="col-3 c-right-col">
          <textarea id="textarea" name="Message" class="text-f" placeholder="Describe your project..."></textarea>
          <button class="link-btn form-btn" type="button">Submit</button>
        </div>
      </form>
    </section>
  </div>
</div>