How to "modularize" a jQuery app?

Question

I want to build a jQuery app that can have multiple instances on a single page.

However, I am running into this problem that one instance receives events from other instances. For example, if I have the following event:

$('#start_btn').click(...)

If any #start_btn on the page is clicked, then all the instances start.

So, how do I design the code so each instance only interacts with the elements within its own HTML code?

Update - If you are here with the same type of question; I found this is the wrong approach. jQuery plugin design is the best approach.

http://learn.jquery.com/plugins/

"If any #start_btn on the page is clicked" -> IDs should be unique... — DarkAjax
– DarkAjax, Commented Jul 18, 2013 at 22:03
I understand about the thing with the ID's. I always follow that guideline. However, I have seen other jQuery apps that work like this: You have segments of HTML with all the same id's and classes, yet the jQuery code can distinguish them from each other as independent apps. — Lee Loftiss
– Lee Loftiss, Commented Jul 18, 2013 at 22:07
I see your point, but other people's bad practices are not a good reason for doing the same thing... — DarkAjax
– DarkAjax, Commented Jul 18, 2013 at 22:08
Sure. Been down that road. But I need to make this app so there are multiple instances on the same page. And this is the only practice I've seen. Perhaps there is a better way to approach this? — Lee Loftiss
– Lee Loftiss, Commented Jul 18, 2013 at 22:11
I'm not sure if localize is the right term. Maybe you mean "modularize"? — jsalonen
– jsalonen, Commented Jul 18, 2013 at 22:26

Joe Enos · Accepted Answer · 2013-07-18 22:01:52Z

2

You should never have two controls with the same ID on the same page. If you want absolutely separated pages, you may want to put each app in its own IFRAME, with its own full context, then they'll be totally segregated.

I suppose it depends on exactly what these things do, and how big and complex everything is.

answered Jul 18, 2013 at 22:01

Joe Enos

40.6k11 gold badges86 silver badges144 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

jsalonen · Accepted Answer · 2013-07-18 22:46:15Z

1

IDs are ment to be unique per-document. Don't use them. Instead, use a general-purpose class attribute to identify individual applications and classes (again) inside these instances too point into specific parts of the application.

Example HTML:

<div class="app">
  <a class="start-button" href="#">button1</a>
</div>
<div class="app">
  <a class="start-button" href="#">button2</a>
</div>

Assuming the above, you can now determine the application in which the start button was clicked:

$('.start-button').click(function(event) {
    var app = $(event.target).closest('.app');
    // Do stuff
});

Now if you want to do stuff inside that specific application, you can just use the app or some other top reference to keep the changes inside that app only.

For instance, hiding the button when clicked:

$(app, '.start-button').hide();

For a full running example, see this Fiddle: http://jsfiddle.net/8Xtue/2/

What I'm presenting here is a simple foundation for a JavaScript application framework. If this is the style you are writing your applications, you might want to consider some ready framework like AngularJS (http://angularjs.org/), which already provides you with a very well thought framework on working this kind of embeddable, JavaScript applications.

edited Jul 18, 2013 at 22:46

answered Jul 18, 2013 at 22:01

jsalonen

30.8k15 gold badges93 silver badges111 bronze badges

4 Comments

Lee Loftiss Over a year ago

This is an interesting idea. Now, if someone clicks the button for appId 1, and something needs to happen, such as displaying a specific DIV, how would I access it the copy of that DIV in the appId1 and not appId2?

ginman Over a year ago

This solution works, but it is definitely over-engineered for the problem you're looking to solve. I avoid data attributes whenever I can, because they just add another layer of complexity to the HTML/JS interaction. This also makes it more difficult to re-use templated HTML, such as your start button here.

jsalonen Over a year ago

Definitely agree on the over-engineering part. Edited to remove IDs and data-attributes since they are not actually required. I archived the old version here just in case somebody wants to look it up: jsfiddle.net/8Xtue/1

Lee Loftiss Over a year ago

I accepted this answer because, for the scenario I gave, it seems to be the most appropriate. However, in my search, I discovered I was taking the wrong approach. I read about jQuery plugin design and realized that was the correct approach. learn.jquery.com/plugins

ginman · Accepted Answer · 2013-07-18 22:41:39Z

0

You can namespace your controls.

If you post the code for your page, i can update this answer, however this is what it might look like

<div id="page1">
  <button class=".startBtn">
</div>
<div id="page2">
  <button class=".startBtn">
</div>

Then in the jquery

$("#page1 > .startBtn").click()
$("#page2 > .startBtn").click()

OR, if they are not direct parent child

$(".startBtn", "#page1").click()
$(".startBtn", "#page2").click()

Some documentation here: http://api.jquery.com/child-selector/

NOTE: I changed the startBtn to a class instead of an ID, as we generally want to avoid having duplicate IDs within the DOM.

edited Jul 18, 2013 at 22:41

answered Jul 18, 2013 at 22:29

ginman

1,31510 silver badges20 bronze badges

Collectives™ on Stack Overflow

How to "modularize" a jQuery app?

3 Answers 3

Comments

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related