textarea-autosize

This is a jQuery plugin for vertically adjusting a textarea based on user input and controlling any presentation in CSS. No clone or ghost elements used. 😉

So why build this? Many solutions didn't feel smooth. In some the textarea would flicker on entering new lines with a noticeable delay in resizing. Most were outdated and all were a lot bulkier than they had to be. Many had to use a mirror textarea or ghost element with some needing presentation values set in script. I wanted just the behavior in the script and anything regarding presentation should be controlled through CSS.

Installation

NPM

npm install textarea-autosize

Bower

bower install textarea-autosize

Or add textarea-autosize to your application's bower.json.

  "dependencies": {
    "textarea-autosize": "latest"
  }

Standalone

curl -O https://raw.github.com/javierjulio/textarea-autosize/master/dist/jquery.textarea_autosize.js

Usage

Load the plugin and use jQuery to find the desired textarea elements on which to call the plugin method.

<textarea class="js-auto-size" rows="1"></textarea>

<script src="http://code.jquery.com/jquery-2.1.0.min.js"></script>
<script src="jquery.textarea_autosize.min.js"></script>
<script>
  $('textarea.js-auto-size').textareaAutoSize();
</script>

Minimum CSS Requirements

The only requirement is to set box-sizing: border-box and a min-height on the textarea. In the example below, the minimum height is one line of text which is determined from the base font size, line height, and vertical padding and border.

textarea {
  box-sizing: border-box;
  max-height: 94px; /* optional, but recommended */
  min-height: 31px;
  overflow-x: hidden; /* for Firefox (issue #5) */
}

Increase the min-height to have more initial rows. Once text exceeds that minimum height the textarea will expand naturally. The overflow-x setting is for Firefox to prevent an initial additional line from appearing.

Updating Textarea Content

If you pre-fill the textarea before page load the textarea will adjust to fit automatically but if given a value after page load (e.g. single page app) then you will need to trigger an input event on the textarea after setting its value for it to size correctly.

textarea.val('A test comment.').trigger('input');

Browser Support

These are the browsers I've tested against. These are not requirements.

• Google Chrome (latest)
• Apple Safari 6+
• Mozilla Firefox (latest)
• Internet Explorer 9+ (using ievms)

Contributions

Project setup: npm install

Run tests: npm test

Deploy New Release

Replace {type} with any of the following: patch, minor or major

npm version {type} --no-git-tag-version
bower version {type} -m "Prep %s release"
git push origin --tags
npm publish

Update GitHub Project Page

  git push origin master
  git push -f origin origin/master:gh-pages

Version History

0.4.2 (March 30, 2016)

• Account for vertical border width (#18 - thanks @kulbakin)
• Remove unused variable (#16 - thanks @nomosyn)

0.4.1 (May 7, 2015)

• Default to 0 if no vertical padding set (#11 - thanks @pedroha)

0.4.0 (December 18, 2014)

• Preserving window scroll position whenever textarea height changes (Issue #6)
• Updated suggested CSS to include overflow-x hidden (Issue #5)
• Removed code that accounted for Firefox height issue
• Updated demo sample code to reflect values used for single line textarea

0.3.0 (September 15, 2014)

• Updated demo to use SASS

0.2.0 (June 3, 2014)

• Minor README changes
• Updated gulp related dev dependencies

0.1.0 (April 19, 2014)

• Initial release

Resources

• https://github.com/theproductguy/BetterGrow
• https://github.com/cburgmer/jquery-shiftenter