.attr() rewrite

Splitting apart methods for handling attributes (the things in the HTML) from those for handling properties (of the corresponding DOM Element)

Performance improvements!

Previously, too much magic, too many weird edge cases

Caused some backwards-comaptibilty headaches, so we patched these cases in 1.6.1

Use .attr and .removeAttr for attributes

Use .prop and .removeProp for properties

Protip: Just use actual DOM element properties:

var select = $("#someSelect");
select.prop( "selectedIndex", 3 );
select[0].selectedIndex = 3;

Relative CSS

.css works like .animate

Change CSS properties relative to their current value

$("#wat").css("width", "+=100px")

A better $.map()

You can now $.map through a plain object to produce an array, instead of having to use $.each

var methodNames = $.map( {
  bar: $.noop,
  baz: $.noop
}, function(func, name) {
  return name;
}); // -> // [ "bar", "baz" ]

Effects Improvements

Groups of animations are synced and will finish at the same time

Animations implement Deferreds, have a promise interface

// Traditonal callback will fire for each element in the collection
var stuff = $(".stuff").fadeIn( function() { });

// Use the promise interface to wait for all animations to complete and fire a single callback
$.when( stuff ).done(function( elements ) { });

requestAnimationFrame

Added in 1.6, pulled in 1.6.3 because of bad results with out-of-focus tabs/windows

New Deferred Methods

.always: one callback to rule them all!

.pipe: filttering and chaining Deferreds

New.on and .off methods unify .bind, .delegate, and .live

• $("selector").on( events, fn)

  // Emulates 1.6 .bind
  // Attaches a handler directly to all .foo currently on the page when code is executed
  $(".foo").on("click", function(e) {})
  

• $("selector").on( events, selector, fn)

  // Emulates 1.6 .delegate
  // Attaches a handler to all '.foo' currently on page that will trigger when a '.bar' inside one is clicked
  $(".foo").on("click", ".bar", function(e) {})
  

• $(document).on( events, selector, fn)

  // Emulates 1.6 live
  // Attaches a handler to the document that will trigger when a '.bar' anywhere in the document is clicked
  $(document).on("click", ".bar", function(e) {})
  

• Approximately 50% performance improvement on delivery of delegated events, because we're actually faster than native matchesSelector
• Optimized for most common selectors: Permutations of tag#id.class
• Old APIs aren't being removed for the forseeable future
• But now they're just shortcuts longcuts to .on and .off

Event Property Hooks

• Improved extensibility and speed of the jQuery.Event object
• Granularity in controlling which native event properties are available

// Tells jQuery to include the 'dataTransfer' property on the event object you receive in handlers,
// but only on 'drop' events
jQuery.event.fixHooks.drop = { props: [ "dataTransfer" ] };
$(document).bind("drop", function(e) {
  console.log(e.dataTransfer);
  // Get the actual native event
  console.log( e.originalEvent )
})