Prototype ⇔ jQuery

To and from JavaScript libraries by Remy Sharp¹

¹ Adapted S6 Version from Original PDF Slide Deck

Why Prototype?

• Extends the DOM and core JavaScript objects
• An arsenal of utility functions

Based on Prototype 1.5.1 & 1.6

Why jQuery

• Centred around chaining and binding methods to objects and elements
• Totally encapsulated
• Aims to be exceptionally easy to develop with

Based on jQuery 1.2.1

Differences in Native Support

Non-exhaustive list, and in most case, the functionality can be implemented with plugins.

Syntax Comparison

Dollar Variable

• Prototype uses $ for id based selection
• jQuery $ = CSS based selector (= $$ in Prototype)

Note that Prototype will return element objects or arrays of elements for most methods. jQuery will usually return a jQuery object (which looks like an array in Firebug).

$ Example

Prototype

$('speech1').show();

jQuery

$('#speech1').show();

CSS Based Selectors

• Prototype – $$

To narrow down it’s context use Element.getElementsBySelector(selector) (or Element.select(selector) in 1.6)

• jQuery – $

Virtually all of jQuery’s DOM selection is done using CSS 1-3

Selector Examples

Prototype

$$('.dialog').invoke('show');

$('final-speech').getElementsBySelector('DIV.final-dialog').each(Element.hide);

// 1.6
$('final-speech').select('DIV.final-dialog').invoke('hide');

jQuery

$('.dialog').show();

$('#final-speech DIV.final-dialog').hide();

DOM Ready Event

• Prototype – uses Event object
• jQuery – uses two types of syntax, both meaning the same thing

jQuery uses different methods to execute the ready function when the DOM is ready, using specific methods for Internet Explorer and for Safari¹

¹ window.onload again, The window.onload Problem Revisited

Ready Example

Prototype

Event.observe(window,'load',function(){});

Prototype 1.6

document.observe('contentloaded',function{});

jQuery

$(document).ready(function(){});
 // or
$(function(){});

Iteration

Prototype – current active element, and position is passed in to callback function.

[el1, el2].each(fn(el, i))

jQuery – current element position passed in to callback function, and binds the function to current active element (i.e. this is set to the active element).

$([el1, el2]).each(fn(i))

DOM Walking

Prototype – up, down, next & previous

jQuery – parent/s, children, next, prev (& nextAll, prevAll)

DOM Manipulation

Prototype – Insertion class: After, Before, Bottom, Top, update (1.6 will add: Element.insert)

jQuery – after, before, append, prepend & html

Element Classes

Prototype – addClassName, removeClassName, toggleClassName, hasClassName

jQuery – addClass, removeClass, toggleClass, is (for class matching)

Events

Prototype – Event class: observe, stopObserving (Prototype 1.6 will support Element.observe)

jQuery – bind, unbind (also supports shortcuts: .click, .dblclick, .mouse*, .ready, .focus, .blur)

Bubbling

Prototype – Event.stop()

jQuery – return false or event.stopPropagation() (event is passed in to the callback)

Ajax

Prototype

new Ajax.Request(url[, options])

jQuery

$.ajax(options) // url included in options

Ajax – Method Comparison

Ajax Examples

Prototype

new Ajax.Request('/profile', {
  method: 'post',
  parameters:$H({'action':'check_username','username':$F('username')}),
  onSuccess: function (j) {
    // do stuff with response
  }
});

jQuery

$.ajax({ url: '/profile',
  data: {'action':'check_username','username': $('#username').val()},
  type: 'post',
  success: function (json) {
    // do stuff with response
  }
});

Plugins / Extensions

Prototype

Element.addMethods({myPlugin : function(element, args) { return element; }});

jQuery

jQuery.fn.myPlugin = function (args) { return this; };

Browser Detection

Prototype – Prototype.Browser.IE, .Webkit, etc.

jQuery – jQuery.browser.msie, .safari, etc.

Resources