In order to understand Ajax, you must first understand what a web browser does normally.
As an example, here’s some CoffeeScript code that makes an Ajax request using the jQuery library:
$.ajax(url: “/test”).done (html) -> $(“#results”).append html
This code fetches data from “/test”, and then appends the result to the div with an id of results.
Rails provides quite a bit of built-in support for building web pages with this technique. You rarely have to write this code yourself. The rest of this guide will show you how Rails can help you write websites in this way, but it’s all built on top of this fairly simple technique.
Awkward, right? We could pull the function definition out of the click handler, and turn it into CoffeeScript:
@paintIt = (element, backgroundColor, textColor) -> element.style.backgroundColor = backgroundColor if textColor? element.style.color = textColor
And then on our page:
That’s a little bit better, but what about multiple links that have the same effect?
Not very DRY, eh? We can fix this by using events instead. We’ll add a data-* attribute to our link, and then bind a handler to the click event of every link that has that attribute:
@paintIt = (element, backgroundColor, textColor) -> element.style.backgroundColor = backgroundColor if textColor? element.style.color = textColor $ -> $(“a[data-background-color]”).click (e) -> e.preventDefault() backgroundColor = $(this).data(“background-color”) textColor = $(this).data(“text-color”) paintIt(this, backgroundColor, textColor) Paint it red Paint it green Paint it blue
Rails provides a bunch of view helper methods written in Ruby to assist you in generating HTML. Sometimes, you want to add a little Ajax to those elements, and Rails has got your back in those cases.
You can read below about the different events that are fired dealing with remote elements inside your application.
form_with is a helper that assists with writing forms. By default, form_with assumes that your form will be using Ajax. You can opt out of this behavior by passing the :local option form_with.
<%= form_with(model: @article) do |f| %> … <% end %>
This will generate the following HTML:
Note the data-remote=”true”. Now, the form will be submitted by Ajax rather than by the browser’s normal submit mechanism.
You probably don’t want to just sit there with a filled out
Since it’s just a