Wow. This stuff is so cool. I thought Rails was cool enough, but add in some AJAX, jQuery, some Handlebars formatting, and it’s pretty awesome. I likey! So, I’m writing about my second to last project in the Flatiron Online curriculum. It wasn’t a stand alone project; we were building on top of our previous Rails app, just with with a jQuery front end.

jQuery and AJAX have really changed the game and are the main reasons why apps and the internet in general have grown by leaps and bounds in the last ten years. Let’s face it, if you have JavaScript running in your web app, it’s going to slow down page loads. Enter asynchronous page loading. This allows all of the scripts to load on the page at the same time. This makes page loads much faster by allowing less hoggy things like HTML and CSS to load while the JavasScript is loading at the same time in the background. This allows the user to see the page content before all the JavaScripts are actually loaded. In the old days, you wouldn’t see anything on the page you visited until every script was loaded. How far we’ve come!




The real magic happens when Ajax and jQuery are used together. Ajax allows you to make calls to the database or API behind the scenes, or asynchronously. While jQuery makes it so you can change just what you want on the page (DOM) with the data from your Ajax call. Normally, when a user clicks a button – lets use a comment form, for this example – the following happens:


  • The clicked button will take all of the data user filled in on the form (parameters) for a ride to the associated controllers ‘create’ action, which is specified in the form. This will include the comment itself, and the users id.
  • The ‘create’ action will try to make a new comment in the database but first it has to pass inspection from the associated model. In this example, we’d go the Comment model.
  • If there are any validations for the model, the parameters sent through will have to pass or they will be sent packing and redirecting to the place they came from, with a warning to boot – You must fill in the comment box!
  • Assuming they pass, then a new comment will be created in the database and we’ll be redirected to the show page. We’ll call over to the database for the newly created comment by the parameter id sent along from the create action to the show action.
  • Now we’re ready for a new page load. The page refreshes and we see our new comment.

That’s quite a lot of work and we have to when the page refreshes, it has to load everything all over again. It would be so much better if the page didn’t refresh and just the newly created comment was appended to it. Can this sort of thing happen? Why, yes Bobby, it can. Enter the world of Ajax and jQuery! In simple terms, jQuery will hijack the submit button request and will handle it a little differently. Let’s check it out!

  • Now when our user clicks the submit button on the comment form, jQuery will be listening for this click. Instead of the usual route to the controller action, now the jQuery hijacks the information filled out from the form and we can do what we please with it.
  • Here, we’d serialize the form, which basically puts the pertinent information into JSON (JavaScript Object Notation) and call a handy function called preventDefault on the event. This will prevent our page from reloading, which is its default behavior.
  • With the JSON, we can make our Ajax ‘POST’ call. This will basically start the usual process described above, sending our data to the ‘create’ action of the controller and so on.
  • When the comment is created, we get the success call back to our Ajax function and we can append the data to the DOM with jQuery.

This is the modern web. This is what makes it so cool. From Waze, to Amazon; they work so well, and so damn fast, because of JavaScript, jQuery, and Ajax. I’ve tried to explain this process as simply as possible, but there is much more going on behind the scenes and I will go there in a future post. jQuery is fine for appending simple things to the DOM. But what happens when you want to manipulate quite a bit of information on the DOM? Like this grossness:


YUCK!! This is what templates like Handlebars is great for. While I’m not an expert, I’m going to write about my process of refactoring the ugliness above into a nice and neat   Handlebars template (which I found very confusing at first) and JavaScript Model Objects (prototypes). It will be a series of posts going through the process from ugly to beautiful. My very own makeover show. Heh, that’s a good idea for a show: Coding Makeover. Or maybe: Coding Nightmares. Anyway, until then…





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