还有另一个关于这个的帖子,我试过了。但有一个问题:如果你删除内容,文本区域不会缩小。我找不到任何方法将其缩小到正确的大小- clientHeight值返回为文本区域的完整大小,而不是它的内容。

该页面的代码如下:

function FitToContent(id, maxHeight)
{
   var text = id && id.style ? id : document.getElementById(id);
   if ( !text )
      return;

   var adjustedHeight = text.clientHeight;
   if ( !maxHeight || maxHeight > adjustedHeight )
   {
      adjustedHeight = Math.max(text.scrollHeight, adjustedHeight);
      if ( maxHeight )
         adjustedHeight = Math.min(maxHeight, adjustedHeight);
      if ( adjustedHeight > text.clientHeight )
         text.style.height = adjustedHeight + "px";
   }
}

window.onload = function() {
    document.getElementById("ta").onkeyup = function() {
      FitToContent( this, 500 )
    };
}

当前回答

这适用于我(Firefox 3.6/4.0和Chrome 10/11):

var observe; if (window.attachEvent) { observe = function (element, event, handler) { element.attachEvent('on'+event, handler); }; } else { observe = function (element, event, handler) { element.addEventListener(event, handler, false); }; } function init () { var text = document.getElementById('text'); function resize () { text.style.height = 'auto'; text.style.height = text.scrollHeight+'px'; } /* 0-timeout to get the already changed text */ function delayedResize () { window.setTimeout(resize, 0); } observe(text, 'change', resize); observe(text, 'cut', delayedResize); observe(text, 'paste', delayedResize); observe(text, 'drop', delayedResize); observe(text, 'keydown', delayedResize); text.focus(); text.select(); resize(); } textarea { border: 0 none white; overflow: hidden; padding: 0; outline: none; background-color: #D0D0D0; } <body onload="init();"> <textarea rows="1" style="height:1em;" id="text"></textarea> </body>

如果你想试试jsfiddle 它从一行开始,只增加所需的确切数量。对于一个单一的文本区域是可以的,但是我想写一些东西,我将有很多很多这样的文本区域(大约像一个大文本文档中通常有行一样多)。在这种情况下,它真的很慢。(在Firefox中,它慢得离谱。)所以我真的很喜欢使用纯CSS的方法。这将是可能的contentteditable,但我希望它是纯文本。

其他回答

jQuery的解决方案 请根据实际情况调整CSS

css……

div#container textarea {
    min-width: 270px;
    width: 270px;
    height: 22px;
    line-height: 24px;
    min-height: 22px;
    overflow-y: hidden; /* fixes scrollbar flash - kudos to @brettjonesdev */
    padding-top: 1.1em; /* fixes text jump on Enter keypress */
}

javascript……

// auto adjust the height of
$('#container').delegate( 'textarea', 'keydown', function (){
    $(this).height( 0 );
    $(this).height( this.scrollHeight );
});
$('#container').find( 'textarea' ).keydown();

或替代jQuery 1.7+…

// auto adjust the height of
$('#container').on( 'keyup', 'textarea', function (){
    $(this).height( 0 );
    $(this).height( this.scrollHeight );
});
$('#container').find( 'textarea' ).keyup();

我已经创建了一个具有绝对最小样式的小提琴作为您的实验的起点…… http://jsfiddle.net/53eAy/951/

如果你不需要支持IE8,你可以使用input事件:

var resizingTextareas = [].slice.call(document.querySelectorAll('textarea[autoresize]'));

resizingTextareas.forEach(function(textarea) {
  textarea.addEventListener('input', autoresize, false);
});

function autoresize() {
  this.style.height = 'auto';
  this.style.height = this.scrollHeight+'px';
  this.scrollTop = this.scrollHeight;
  window.scrollTo(window.scrollLeft,(this.scrollTop+this.scrollHeight));
}

现在你只需要添加一些CSS,你就完成了:

textarea[autoresize] {
  display: block;
  overflow: hidden;
  resize: none;
}

用法:

<textarea autoresize>Type here and I’ll resize.</textarea>

你可以在我的博客文章中阅读更多关于它是如何工作的。

稍微更正一下。完美演绎歌剧

  $('textarea').bind('keyup keypress', function() {
      $(this).height('');
      var brCount = this.value.split('\n').length;
      this.rows = brCount+1; //++ To remove twitching
      var areaH = this.scrollHeight,
          lineHeight = $(this).css('line-height').replace('px',''),
          calcRows = Math.floor(areaH/lineHeight);
      this.rows = calcRows;
  });

有人觉得满意吗?没有混乱的滚动,和唯一的JS我喜欢关于它是如果你计划在模糊保存数据…显然,它在所有流行的浏览器上都是兼容的:http://caniuse.com/#feat=contenteditable

只要把它设置成文本框的样式,它就会自动调整大小……将它的最小高度设置为首选文本高度。

这种方法的最酷之处在于,您可以在某些浏览器上保存和标记。

http://jsfiddle.net/gbutiri/v31o8xfo/

var _auto_value = ''; $(document).on('blur', '.autosave', function(e) { var $this = $(this); if ($this.text().trim() == '') { $this.html(''); } // The text is here. Do whatever you want with it. $this.addClass('saving'); if (_auto_value !== $this.html() || $this.hasClass('error')) { // below code is for example only. $.ajax({ url: '/echo/json/?action=xyz_abc', data: 'data=' + $this.html(), type: 'post', datatype: 'json', success: function(d) { console.log(d); $this.removeClass('saving error').addClass('saved'); var k = setTimeout(function() { $this.removeClass('saved error') }, 500); }, error: function() { $this.removeClass('saving').addClass('error'); } }); } else { $this.removeClass('saving'); } }).on('focus mouseup', '.autosave', function() { var $this = $(this); if ($this.text().trim() == '') { $this.html(''); } _auto_value = $this.html(); }).on('keyup', '.autosave', function(e) { var $this = $(this); if ($this.text().trim() == '') { $this.html(''); } }); body { background: #3A3E3F; font-family: Arial; } label { font-size: 11px; color: #ddd; } .autoheight { min-height: 16px; font-size: 16px; margin: 0; padding: 10px; font-family: Arial; line-height: 20px; box-sizing: border-box; -o-box-sizing: border-box; -moz-box-sizing: border-box; -webkit-box-sizing: border-box; overflow: hidden; display: block; resize: none; border: 0; outline: none; min-width: 200px; background: #ddd; max-height: 400px; overflow: auto; } .autoheight:hover { background: #eee; } .autoheight:focus { background: #fff; } .autosave { -webkit-transition: all .2s; -moz-transition: all .2s; transition: all .2s; position: relative; float: none; } .autoheight * { margin: 0; padding: 0; } .autosave.saving { background: #ff9; } .autosave.saved { background: #9f9; } .autosave.error { background: #f99; } .autosave:hover { background: #eee; } .autosave:focus { background: #fff; } [contenteditable=true]:empty:before { content: attr(placeholder); color: #999; position: relative; top: 0px; /* For IE only, do this: position: absolute; top: 10px; */ cursor: text; } <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <label>Your Name</label> <div class="autoheight autosave contenteditable" contenteditable="true" placeholder="Your Name"></div>

如果scrollHeight可以信任,那么:

textarea.onkeyup=function() {
  this.style.height='';
  this.rows=this.value.split('\n').length;
  this.style.height=this.scrollHeight+'px';
}