CSS Textarea that expands as you type text [duplicate]

Answer 1

var textarea = document.querySelector('textarea');
textarea.addEventListener('keydown', autosize);             
function autosize(){
  var el = this;
  setTimeout(function(){
    el.style.cssText = 'height:auto; padding:0';    
    el.style.cssText = 'height:' + el.scrollHeight + 'px';
  },0);
}

textarea{   
  overflow:hidden; 
  padding:10px;
  width:250px;
  font-size:14px;
  margin:50px auto;
  display:block;
  border-radius:10px;
  border:6px solid #556677;
}

CSS Textarea that expands as you type text
rows Specifies the visible number of lines in a text area and cols	Specifies the visible width of a text area