Why is there no spell checking in title and edit summary?

Question

Why is there only a spell checking capability in the main body? Why not the title and the edit summary field too (if you are editing a question)?

Answer 1

Because the title is

<input id="title" name="title" type="text" maxlength="300" tabindex="100" placeholder="What's your bug, feature request, or meta-discussion topic? Be specific." class="ask-title-field" data-min-length="15" data-max-length="150"> 

and the text is:

<textarea id="wmd-input" class="wmd-input" name="post-text" cols="92" rows="15" tabindex="101" data-min-length=""></textarea>

and FireFox only check text areas for spelling errors.

To change that behaviour open an about:config tab, filter for layout.spellcheckDefault, double click the value and change it to 2.

Done!

Answer 2

Spellchecking isn't something done by the website but rather something done by the browser.

The main body is a single <textarea> which browsers typically assume will be used for composing long blocks of text and enable basic spellchecking automatically. The title and edit summary controls are instead <input type="text"> fields and browsers typically do not enable spellchecking for them.

On a related note, the HTML5 spellcheck attribute can provide browsers with a hint as to which controls should have spellcheck enabled. This table shows the browser support for this attribute.