Zepto 1.1: Moar performance, IE 10+, Deferreds

Mislav and I just released Zepto 1.1, which brings updates across the board. Even if you don’t need to new features, upgrading is worth it for “free” IE 10 support (which makes mobile sites work great on Windows Phone 8) as well as the huge performance speedups for common operations (benchmarks).

Notable changes

• IE10+ support
• Huge speed optimizations for simple CSS selectors (classname, ID) and DOM element creation
• Provide $.Callbacks and $.Deferred in optional modules
• Removed fx and detect modules from default build

Ajax

• New supported $.ajax() options:
  • xhrFields
  • mimeType
  • jsonpCallback
  • username & password
• Promise interface supported when loading the optional “callbacks” and “deferred” modules:
  • xhr.done(function(data, status, xhr){ ... })
  • xhr.fail(function(xhr, errorType, error){ ... })
  • xhr.always(function(){ ... })
• Enable mutating Ajax settings in the beforeSend callback
• Fix JSONP callbacks for errored responses on Android
• Ensure consistent Accept request HTTP header across browsers
• Fix $.param() for jQuery compatibility when handling complex nested objects
• Support IIS JavaScript MIME type
• Pass “abort” and “timeout” status to global ajaxError event handlers

Event

• Provide isDefaultPrevented(), stopImmediatePropagation(), and related methods for all events
• Support the data argument in .bind(), .on(), and .one()
• Support CSS selector argument in .one() for event delegation
• Support .on('ready') as an alias for .ready()
• Enable event handlers on plain old JS objects
• Many fixes related to event delegation

Data

• Cleanup .data() values on DOM element removal with .remove/empty()
• .data() now assumes that numbers that begin with zeroes are strings
• .removeData() (no argument) now removes all data on the element
• Enable reading data-* attributes that have underscores in the name

Other updates

• Support simple DOM property names in .prop(name) such as for, class, readonly…
• Implement the .scrollLeft([value]) method
• Support setting .scrollTop(value)
• Fix $(document).width/height()
• Support fetching multiple CSS values via array in .css(['prop1', 'prop2', ...])
• Support setting CSS transition delay via delay option for .animate()
• Ensure that .animate() callback always fires

All in all, our most bestest release yet. A big thank-you to all our contributors for making this awesome! 🙂