Creating a textarea with auto-resize

Question

asked Sep 5, 2019 in Web Technology by Tech4ever (20.3k points)

There was another thread about this, which I've tried. But there is one problem: the textarea doesn't shrink if you delete the content. I can't find any way to shrink it to the correct size - the clientHeight value comes back as the full size of the textarea, not its contents.

The code from that page is below:

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 )
};
}

1 Answer

Soni Kumari · Answer 1 · 2019-09-05T10:07:43+0000

Try using the code given below:

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>

Note: This works for Firefox 3.6/4.0 and Chrome 10/11):

You can just use it: http://jsfiddle.net/hmelenok/WM6Gq/

It will start with a single line and grows only the exact amount necessary. It will be ok for a single textarea, but If you want to write something where you can have many such textareas (about as much as one would normally have lines in a large text document). In that case, it will be slow. (In Firefox it's insanely slow.) So you can use CSS and use the plaintext.

Creating a textarea with auto-resize

1 Answer

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