The document announces the alpha release of jQuery version 3.0 and jQuery Compat version 3.0. jQuery 3.0 only supports modern browsers while jQuery Compat 3.0 maintains backwards compatibility. Some key changes in jQuery 3.0 include simplified .show() and .hide() methods, handling of special characters in .data() names, decimal values for width/height, and major speed improvements for custom selectors and animations.
2. jQuery comes in two versions:
A backwards browser compatible version,
currently at version 1.11.1
A more modern version, which no longer
supports older browsers like IE8. Currently at
version 2.1.1
The new release of jQuery is not a major rework of the API like
that announced by Angular for example. The design doesn't
actually need a lot of changes but simply some optimisations.
4. There are actually two versions here:
jQuery Compat 3.0: the browser compatible
version. This library will support all browsers and
most versions. This will lead to a larger file size
and a potential lower performance.
jQuery 3.0: this version will only support the
most common browsers with the current version
and the previous versions. This library will be a
lot slimmer and will perform faster.
5. Simplified .show() and .hide() methods
Everyone’s mental model of jQuery’s .hide() method is that it sets display:
none in CSS. Conversely, .show() clears the display so that the element shows
again (assuming its parents are not hidden).
Special case with .data() names
These changes will mainly come into play when retrieving all data by
calling .data() with no arguments
6. .width(), .height(), .css(“width”), and
.css(“height”) to return decimal values
(whenever the browser does)
Previously, jQuery rounded values when retrieving width and height.
.unwrap( selector )
Unwrap simple removes the parent of selected elements, and accepts no
arguments. In some cases it may be desirable to unwrap only if a condition on
the parent is met.
7. Massive speedups for some jQuery custom selectors
Thanks to some detective work by Paul Irish at Google, we identified some
cases where we could skip a bunch of extra work when custom
selectors like :visible are used many times in the same document. That
particular case is up to 17 times faster now!
Animations now use requestAnimationFrame
On platforms that support the requestAnimationFrame API, which is pretty
much everywhere but IE8 and IE9, jQuery will now use that API when
performing animations. This should result in animations that are smoother
and use less CPU time – and save battery as well on mobile devices.