Html – CKEditor automatically strips classes from div

ckeditorclasshtml

I am using CKEditor as a back end editor on my website. It is driving me round the bend though as it seems to want to change the code to how it sees fit whenever I press the source button. For example if I hit source and create a <div>…

<div class="myclass">some content</div>

It then for no apparent reason strips the class from the <div>, so when I hit source again it has been changed to…

<div>some content</div>

I presume this irritating behaviour can be turned off in the config.js, but I have been digging and cant find anything in documentation to turn it off.

Best Answer

Disabling content filtering

The easiest solution is going to the config.js and setting:

config.allowedContent = true;

(Remember to clear browser's cache). Then CKEditor stops filtering the inputted content at all. However, this will totally disable content filtering which is one of the most important CKEditor features.

Configuring content filtering

You can also configure CKEditor's content filter more precisely to allow only these element, classes, styles and attributes which you need. This solution is much better, because CKEditor will still remove a lot of crappy HTML which browsers produce when copying and pasting content, but it will not strip the content you want.

For example, you can extend the default CKEditor's configuration to accept all div classes:

config.extraAllowedContent = 'div(*)';

Or some Bootstrap stuff:

config.extraAllowedContent = 'div(col-md-*,container-fluid,row)';

Or you can allow description lists with optional dir attributes for dt and dd elements:

config.extraAllowedContent = 'dl; dt dd[dir]';

These were just very basic examples. You can write all kind of rules - requiring attributes, classes or styles, matching only special elements, matching all elements. You can also disallow stuff and totally redefine CKEditor's rules. Read more about:

Content filtering in CKEditor – why do you need content filter.
Advanced Content Filter – in deep description of the filtering mechanism.
Allowed content rules – how to write allowed content rules.

2015 update: the flexbox approach

There are two other answers briefly mentioning flexbox; however, that was more than two years ago, and they don't provide any examples. The specification for flexbox has definitely settled now.

Note: Though CSS Flexible Boxes Layout specification is at the Candidate Recommendation stage, not all browsers have implemented it. WebKit implementation must be prefixed with -webkit-; Internet Explorer implements an old version of the spec, prefixed with -ms-; Opera 12.10 implements the latest version of the spec, unprefixed. See the compatibility table on each property for an up-to-date compatibility status.

(taken from https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Flexible_boxes)

All major browsers and IE11+ support Flexbox. For IE 10 or older, you can use the FlexieJS shim.

To check current support you can also see here: http://caniuse.com/#feat=flexbox

Working example

With flexbox you can easily switch between any of your rows or columns either having fixed dimensions, content-sized dimensions or remaining-space dimensions. In my example I have set the header to snap to its content (as per the OPs question), I've added a footer to show how to add a fixed-height region and then set the content area to fill up the remaining space.

html,
body {
  height: 100%;
  margin: 0;
}

.box {
  display: flex;
  flex-flow: column;
  height: 100%;
}

.box .row {
  border: 1px dotted grey;
}

.box .row.header {
  flex: 0 1 auto;
  /* The above is shorthand for:
  flex-grow: 0,
  flex-shrink: 1,
  flex-basis: auto
  */
}

.box .row.content {
  flex: 1 1 auto;
}

.box .row.footer {
  flex: 0 1 40px;
}

<!-- Obviously, you could use HTML5 tags like `header`, `footer` and `section` -->

<div class="box">
  <div class="row header">
    <p><b>header</b>
      <br />
      <br />(sized to content)</p>
  </div>
  <div class="row content">
    <p>
      <b>content</b>
      (fills remaining space)
    </p>
  </div>
  <div class="row footer">
    <p><b>footer</b> (fixed height)</p>
  </div>
</div>

In the CSS above, the flex property shorthands the flex-grow, flex-shrink, and flex-basis properties to establish the flexibility of the flex items. Mozilla has a good introduction to the flexible boxes model.

Html – How to make a div not larger than its contents

The solution is to set your div to display: inline-block.

Best Answer

Disabling content filtering

Configuring content filtering

Related Solutions

Html – Make a div fill the height of the remaining screen space

2015 update: the flexbox approach

Working example

Html – How to make a div not larger than its contents

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