Never been to TextSnippets before?

Snippets is a public source code repository. Easily build up your personal collection of code snippets, categorize them with tags / keywords, and share them with the world (or not, you can keep them private!)

About this user

Jamie Wilkinson http://tramchase.com

« Newer Snippets
Older Snippets »
5 total  XML / RSS feed 

jQuery namespaced event binding/unbinding

// from a comment by Steven Bristol on errtheblog.com

I just wanted to share a really killer event handling tidbit:

Generally you do something like:

jQuery(’.class’).click(function(){//whatever});


Everyone knows this can be rewritten as:

jQuery(’.class’).bind(‘click’, function(){//whatever});


But sometimes you need to unbind something:

jQuery(’.class’).unbind(‘click’, function(){//});


The problem with this is that it will unbind all the click events, not just yours. So if multiple bits of javascript have a click event handler for ’.class’, unbinding removes them all. (This is because there is no way to identify an anonymous function.)

But jQuery is so good that there is a way to handle this: Namespacing your events:

jQuery(’.class’).bind(‘click.namespace’, function(){//}); 
jQuery(’.class’).unbind(‘click.namespace’);


or for reinitializing an element added via ajax:

jQuery(’.class’)unbind(‘click.namespace’).bind(‘click.namespace’, function(){//});

jQuery and Rails' respond_to

// Just throw this at the bottom of your application.js and you’re good to go: all jQuery ajax requests will trigger the wants.js block of your respond_to declaration, exactly like you’d expect. Enjoy.
// via: http://ozmm.org/posts/jquery_and_respond_to.html

jQuery.ajaxSetup({beforeSend’: function(xhr) {xhr.setRequestHeader(“Accept”,text/javascript”)} })

Never render the full layout in a Rails view when called via AJAX

Essential for degradable javascript, when one never knows if a view or partial is being called via XmlHttpRequest or not. Throw the below code in your ApplicationController (application.rb)

More info in this blog post

def render(*args)
        args.first[:layout] = false if request.xhr? and args.first[:layout].nil?
        super
end

ajax_request? method to XHR detection

A oneline helper I put in all of my apps. Looks for HTTP headers that signal you're being called via an XmlHttpRequest. I use it for instant degradable AJAX by rendering a template if it's as usual but just rendering a partial if they just want that part!

  def ajax_request?
    request.env['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest' || params[:ajax]  # params[:ajax] for safe-keeping, FIXME if it works w/ all browsers
  end

Increase the number of simultaneous XmlHttpRequests in Firefox

Firefox doesn't do a lot of simultaneous AJAX (or any kind of HTTP) requests. IE caps it at 2, too. This will allow you to test your XHR overload scripts, or just load pages faster in general.

1. Go to "about:config"
2. Find and edit the following
* network.http.pipelining=false
* network.http.pipelining.maxrequests=4
* network.http.proxy.pipeline=false
3. Make the false's true; I set my maxrequests at 20
« Newer Snippets
Older Snippets »
5 total  XML / RSS feed