HTML

html textarea height

<!-- textarea rows attribute -->
<textarea id="txtid" name="txtname" rows="4" cols="50" maxlength="200">
A nice day is a nice day.
Lao Tseu
</textarea>

text area height

<label for="story">Tell us your story:</label>

<textarea id="story" name="story"
          rows="5" cols="33">
It was a dark and stormy night...
</textarea>

html textarea auto height to amount of text

$('textarea').each(function () {
  this.setAttribute('style', 'height:' + (this.scrollHeight) + 'px;overflow-y:hidden;');
}).on('input', function () {
  this.style.height = 'auto';
  this.style.height = (this.scrollHeight) + 'px';
});

get height of text in textarea

ele.scrollHeight (Height of text inside scroll inlduing what u cant see)
ele.clientHeight (What u see)