jQuery+ Ruby + Rails

AppFolio - September 2007

Yehuda Katz (yehudakatz.com)

What is jQuery?

• An open source JavaScript library that simplifies the interaction between HTML and JavaScript.

• Fully documented

• Great community

• Tons of plugins

• Small size (14kb)

• Everything works in IE 6+, Firefox,Safari 2+, and Opera 9+

Why jQuery?

Complete Focus:

• Find some elements

• Do something with them

Find Some Elements...

• CSS 1-3 Support

• Basic XPath via a Plugin

• Better CSS support than most browsers

$(“div”)

<div id=”body”> <h2>Some Header</h2> <div class=”contents”> <p>...</p> <p>...</p> </div></div>

$(“#body”)

<div id=”body”> <h2>Some Header</h2> <div class=”contents”> <p>...</p> <p>...</p> </div></div>

$(“div > div”)

<div id=”body”> <h2>Some Header</h2> <div class=”contents”> <p>...</p> <p>...</p> </div></div>

$(“div:has(div)”)

<div id=”body”> <h2>Some Header</h2> <div class=”contents”> <p>...</p> <p>...</p> </div></div>

• Events (click, hover, toggle, namespaces)

• DOM Manipulation (append, prepend, remove)

• Effects (hide, show, slideDown, fadeOut, stop, relative, queues, %/em, colors)

• AJAX (load, get, post, XD, JSONP)

Features

Events

• $(“form input:last”).click(function(){ $(“#menu”).slideDown(“slow”);});

Live Events

• $(“form input:last”).livequery(“click, function(){ $(“#menu”).slideDown(“slow”); });

• With LiveQuery Official Plugin

DOM Manipulation

• $(“a[target]”) .append(“ (Opens in New Window)”);

• $(“#body”).css({ border: “1px solid green”, height: “40px”});

Effects

• $(“#menu”).slideDown(“slow”);

• $(“div”).hide(500,function(){ $(this).show(500);});

Relative Animations

• $(“#foo”).animate({ left: “+50px” top: “-50px”}, “slow”)

AJAX

• $(“#body”).load(“sample.html”);

• $(“#body”).load(“sample.html #foo”);

• $.getScript(“test.js”);

• $.getScript(“http://jquery.com/jquery.js”);

• $(“div”).hide();

• $(“div”).hide().color(”blue”);

• $(“div”).hide().color(”blue”).slideDown();

Chaining

Live Demo

Accordion Menu

Plugins

• Drag and Drop

• Sortables

• Tabbed Navigation

• Sortable Tables

• And hundreds more...

• http://jquery.com/plugins

• Very active mailing list

• 140+ Posts/Day

• 2500+ Members

• Technorati: 22+ blog posts per day

Community

Who uses jQuery?• IBM

• MSNBC

• Amazon

• AOL

• Technorati

• Drupal

• Wordpress

• Digg

• BBC

• SourceForge

• Intuit

• Salesforce

• FeedBurner

• WB Records

• Linux.com

• many others...

Books

• 4 Books in Progress:

• Learning jQuery (Packt)

• jQuery Reference (Packt)

• jQuery Quickly (Manning)

• Designing with jQuery (Manning)

Future

• “jQuery UI” - Next Sunday!

• Themeing

• Internationalization

Using jQuery with Rails

• Most jQuery use is not different than normal jQuery use

• $(“div”).remove(); // works on any site

• Considerations come mainly in with dealing with Ajax requests

Ajax and Rails

• Just another request to a controller/action

• You might want to respond like so: respond_to do |format| format.js { # do stuff } end

• jQuery sends the right headers so you can respond easily

Ajax with jQuery

• Typically, you’ll reply with an HTML chunk

• jQuery handles this gracefully:$(“#stuff”).load(“/controller/action”);

Reply with JSON

• Sometimes you’ll want to reply with a data structure for further manipulation

• ActiveRecord objects have to_json serialization built in:"{attributes:{foo: \"bar\", baz: \"bat\"}}"

• Or you can get specific: @ar_object.attributes.to_json #=> "{foo: \"bar\", baz: \"bat\"}"

Where does the JS go?

• jQuery dictates good separation of content, style, and behavior

• Put all your code in application.js (just like style.css)

• jQuery and Prototype can play nicely together: jQuery.noConflict(); jQuery(function($){ /* your code */ });

Where’s RJS?

• RJS says that sending back code (from the server) is the best way to do things

• This is overkill, simplify and extract what you’re trying to achieve

RJS v. jQuery-style

• With RJS:<a href=”#” id=’myid’ onclick=”return someFunction(‘myid’);”>text</a><a href=”#” id=’myid2’ onclick=”return someFunction(‘myid2’);”>text</a>

• With jQuery:<a href=”...” id=”myid”>text</a><a href=”...” id=”myid2”>text</a><script>$(“a”).click(someFunction);</script>

jQuery & RJS

• jQuery Doesn’t Agree with the philosophy that produced RJS

• Send data, not code

Helpers

• Say you have a link that makes an Ajax call and updates some div with the response:<a href='/foo/bar' rel='#baz' class='remote'>Update Baz</a>

• You might write a simple line of jQuery code to handle it:$("a.remote").click(function() { $(this.rel).load(this.href) })

Helpers (cont.)

• You could then write a Rails helper to reuse it:def remote_link text, url_hash, update = nil link_to(text, url_hash, :class => "remote", :rel => update)end

• You could then call it as:remote_link "Update Baz", {:controller => "foo", :action => "bar"}, "#baz"

You still have your helpers :)

jQuery on Rails

• Mainly Proof-of-Concept

• Uses Hpricot to select jQuery snippets

• Includes (POC) helpers for

• Tab field

• Sortable table

• More coming

More info:

• jQuery with Rails:

• http://yehudakatz.com/2007/01/31/using-jquery-in-rails-part-i/

• http://yehudakatz.com/2007/05/18/railsconf-talk-recap/

• jQuery Rails Plugin:

• http://yehudakatz.com/2007/05/17/jquery-on-rails-a-fresh-approach/

• http://yehudakatz.com/2007/05/25/10/

• http://yehudakatz.com/2007/05/26/jquery-on-rails-a-still-very-alpha-update/

jquery.comdocs.jquery.com - jquery.com/plugins

More:

visualjquery.comlearningjquery.com