Rich, interactive web applications AKA fat clients are now commonplace. There are so many frameworks for building these rich client applications, and the debate among developers is which of these frameworks to use. As designers and developers we need to step back, and ask ourselves when and how we should enrich our client applications and when or why not. Let’s dig in to the question: Why do we even want fat clients, and when should we use them? Let’s examine the complications such clients introduce so we can weigh them against all the benefits.
2. TIFFANY CONROY
@theophani
All content licensed under http://creativecommons.org/licenses/by-nc-sa/3.0/
My name is Tiffany, and I work as an interaction designer and front-end developer at
SoundCloud.
3. CUTTING THE FAT
When to use Ajax and when to reload
When to use Ajax and when to reload
=======================
This is a talk about being pragmatic.
This is a talk is about how to reduce the technical complexity of web applications.
This talk is about using interaction design to help make the choice between using Ajax and
reloading the page.
4. Last summer there was a conference called “Throne of JS”
The conference had a very specific premise:
5. “Throne of JS … is …
focused on answering
the question on every
web developer’s mind:
“Throne of JS is […] focused on answering the question on every web developer's mind: which
framework?”
Yes: rich, interactive web applications are now commonplace. There are so many frameworks
for building these rich client applications, and the debate among developers is which of these
frameworks to use.
6. “Throne of JS … is …
focused on answering
the question on every
web developer’s mind:
which framework?”
“Throne of JS is […] focused on answering the question on every web developer's mind: which
framework?”
Yes: rich, interactive web applications are now commonplace. There are so many frameworks
for building these rich client applications, and the debate among developers is which of these
frameworks to use.
7. Question the premise.
The premise of the question “which framework” is based on the idea that in a modern web
application, the page should never be reloaded.
But as designers and developers, we need to step back, and ask ourselves: why don’t we want
to reload the page? When *can* we reload the page, and What is the benefit of Ajax? What is
the cost of using Ajax?
Frameworks help up to solve technical problems, but can we ever avoid those problems
entirely?
8. What to expect
First I’m going to define some terminology.
Then we examine the benefits and problems of fancy single-page web applications.
Lastly, I want to show you one way of approaching your applications as a designer and
developer that can help you reduce complexity, even before you choose a framework.
Let’s get started.
9. What to expect
• Terminology
First I’m going to define some terminology.
Then we examine the benefits and problems of fancy single-page web applications.
Lastly, I want to show you one way of approaching your applications as a designer and
developer that can help you reduce complexity, even before you choose a framework.
Let’s get started.
10. What to expect
• Terminology
• Benefits and costs of Ajax
First I’m going to define some terminology.
Then we examine the benefits and problems of fancy single-page web applications.
Lastly, I want to show you one way of approaching your applications as a designer and
developer that can help you reduce complexity, even before you choose a framework.
Let’s get started.
11. What to expect
• Terminology
• Benefits and costs of Ajax
• A pragmatic approach
First I’m going to define some terminology.
Then we examine the benefits and problems of fancy single-page web applications.
Lastly, I want to show you one way of approaching your applications as a designer and
developer that can help you reduce complexity, even before you choose a framework.
Let’s get started.
12. AJAX vs RELOAD
A quick recap for everyone on what Ajax is and what we use it for, and how it differs from a
page reload.
13. In the early 90s, all web pages were static, and if you wanted to see new content, you
followed a link or clicked on a form submit button …
14. In the early 90s, all web pages were static, and if you wanted to see new content, you
followed a link or clicked on a form submit button …
… and the whole page would reload.
15. Whole page
reloads
In the early 90s, all web pages were static, and if you wanted to see new content, you
followed a link or clicked on a form submit button …
… and the whole page would reload.
20. Asynchronous
JavaScript
and
XMLHttpRequest
In 2005, the technique of loading content asynchronously with JavaScript was given the name
Ajax. Around that time Google released Gmail and Google Maps.
(ps to big know-it-alls reading these speaker notes: yes, I know the X originally stood for XML, but making that distinction would just complicate
things.)
21. Just one part
reloads
Ajax allowed us to change the page content without a full page reload.
But the more exciting use case was to make the page send and load content based on user
interaction.
25. Without me doing anything, and without interrupting me typing, the Facebook app uses Ajax
to load information about the link I entered, and adds it to my message.
26. When I send the message, the app uses Ajax to send my message without reloading the page.
Ajax allowed us to maintain the context of what the user was doing, without reloading the
page.
27. Ajax → maintains context
The web stopped being a collection of static web sites with fixed content, and allowed us to
exchange data with the web server without reloading the page.
Now, we rely heavily on Ajax to control the user's experience.
To reiterate what I said before:
Ajax allows us to maintain the context of what the user was doing, without reloading the
page.
29. “Context” is the answer to the question: where are you, and what are you doing. By this I am
not talking about where you physically are while using a web application, but where you are
*within* the web application, and what you are doing there.
30. User
Profile
News
Feed
Store
Checkout
Slideshow
Some examples of different contexts could be:
user profile, a news feed, the checkout of a store, a slideshow.
Within each of these contexts, we may not want to reload the page.
Each distinct context could be its own “single-page app”, and a plain old browser refresh
could be used to transition between these contexts.
31. But two different instances of the same “screen” are in fact two different contexts.
For example: The timeline of two different people are two different contexts.
32. Two separate contexts
But two different instances of the same “screen” are in fact two different contexts.
For example: The timeline of two different people are two different contexts.
33. ✓
Multiple parts of the same workflow can all happen in the same context.
In this example, the context is filling out a form. While the user is in this context, we want to
control the user’s experience as much as possible, so that the user doesn’t lose context.
34. ✓
Same context
Multiple parts of the same workflow can all happen in the same context.
In this example, the context is filling out a form. While the user is in this context, we want to
control the user’s experience as much as possible, so that the user doesn’t lose context.
35. Your application may have lots of little components and features and bits of information, and
you need to understand out how they all relate to each other.
36. Then you need to define which components go together.
37. Then you need to define which components go together.
38. So when I say a context, I mean these different groupings of related bits organized into
meaningful groupings.
Designers need to understand, define and communicate the distinct contexts in any rich web
application, being clear about the where boundaries between contexts are; where one stops
and the next one starts.
39. When we make a transition from one context to the next, we exit the boundary of one
context and enter another.
Ajax could be used to control the transition between contexts, if the designer and the
developer can negotiate it by balancing the benefits against the technical costs.
40. Designers need to understand, define and communicate the distinct contexts in any rich web
application, being clear about the where boundaries between contexts are; where one stops
and the next one starts.
41. Ajax → maintains context
So, Ajax allows us to maintain context for users.
42. Lots of Ajax → “Fat Client”
Web applications that use a lot of Ajax are sometimes called “fat client”
43. FAT vs THIN
What is a “fat” client?
What do we mean by a “fat client”.
How is it different from a “thin client”
44. Client = code in the browser
SERVER ----[ network ]----> CLIENT
## Server and client
In this discussion, the code that runs in a web browser is the “client”, in contrast with code
that runs on a web server.
45. Thin client
DATA + ALL THE LOGIC
-------------------[ network ]---------------->
PRESENTATION
## Thin Client
[ DATA ] + [ ALL THE LOGIC ] ----[network]----> [PRESENTATION]
All the logic is performed on the server-side.
Static pages that rely on page reload are THIN. The browser, AKA the client, just displays the
content.
46. Fat client
DATA
-------------------[ network ]---------------->
ALL THE LOGIC + PRESENTATION
## Fat Client
[ DATA ] + [ ALL THE LOGIC ] ----[network]----> [PRESENTATION]
All the logic is performed on the client-side.
The server sends static content over the network, and all the logic is done in the browser AKA
the client.
These fat clients rely on a lot of JavaScript and Ajax.
47. “Native Experience”
People also talk about a “native experience” on the web.
Ajax allows us to emulate a “native experience” on the web, meaning, it feels like an
application not a web site.
48. “Native Experience”
and controlling transitions
One of the most basic features of a ”native” experience is the controlled transitions between
contexts, for example, the sliding left and right between screens.
On the web, if you reload the page, you can’t define the transition. In every browser I’ve used,
the transition is the same: the page goes white, the spinner spins, and then the page loads.
Reloading can be jarring.
We can get around this if we load the content with Ajax, and then transition to the new
context. We call these sort of sites that exclusively use Ajax “single-page apps”.
49. SINGLE-PAGE APPS
Awesome or not awesome?
So called “single-page apps” are very sexy these days. But people have begun to see that
single-page apps are also nasty beasts that bring all sorts of technical complications with
them.
50. SINGLE-PAGE APPS
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
51. back button
SINGLE-PAGE APPS
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
52. back button
SINGLE-PAGE APPS
deep-linking
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
53. back button
SINGLE-PAGE APPS
deep-linking
#! hash-bang
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
54. JavaScript router
back button
SINGLE-PAGE APPS
deep-linking
#! hash-bang
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
55. JavaScript router
back button
SINGLE-PAGE APPS
deep-linking
#! hash-bang
window.history
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
56. JavaScript router
back button
SINGLE-PAGE APPS
frameworks
deep-linking
#! hash-bang
window.history
Trying to recreate a native experience brings with it all kinds of technical problems.
One upon a time, if the URL in the browser changed, the page reloaded.
As we made rich applications using Ajax, we ran into the problem that we could reach a state
in the application that we could not link to. We started to talk about how to “deep-link” to a
context within an application.
This wasn’t (usually) a problem before we started using Ajax.
57. Let’s pause for a moment:
Why do we want to use Ajax?
What problems are we trying to solve with Ajax? i.e. what **benefits** do we gain from using
it?
58. Problems a fat client solves:
Problems a fat client solves:
* The user can continue to interact (including simply viewing) while data is exchanged.
* The designer can customize and control the loading and transition experience between
contexts.
* Information can be presented in a partial, incremental, incomplete form, thus context can
be established while further information is retrieved. (Like a pan in a film, setting can be
established in advance of details.)
* The traffic between server and client can be reduced to data separate from the presentation,
reducing network use and speeding up information transmission.
Most of these are design problems. Even improved speed would result in a better experience
for people.
59. Problems a fat client solves:
• Continuous interaction
Problems a fat client solves:
* The user can continue to interact (including simply viewing) while data is exchanged.
* The designer can customize and control the loading and transition experience between
contexts.
* Information can be presented in a partial, incremental, incomplete form, thus context can
be established while further information is retrieved. (Like a pan in a film, setting can be
established in advance of details.)
* The traffic between server and client can be reduced to data separate from the presentation,
reducing network use and speeding up information transmission.
Most of these are design problems. Even improved speed would result in a better experience
for people.
60. Problems a fat client solves:
• Continuous interaction
• Transitions between contexts
Problems a fat client solves:
* The user can continue to interact (including simply viewing) while data is exchanged.
* The designer can customize and control the loading and transition experience between
contexts.
* Information can be presented in a partial, incremental, incomplete form, thus context can
be established while further information is retrieved. (Like a pan in a film, setting can be
established in advance of details.)
* The traffic between server and client can be reduced to data separate from the presentation,
reducing network use and speeding up information transmission.
Most of these are design problems. Even improved speed would result in a better experience
for people.
61. Problems a fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Problems a fat client solves:
* The user can continue to interact (including simply viewing) while data is exchanged.
* The designer can customize and control the loading and transition experience between
contexts.
* Information can be presented in a partial, incremental, incomplete form, thus context can
be established while further information is retrieved. (Like a pan in a film, setting can be
established in advance of details.)
* The traffic between server and client can be reduced to data separate from the presentation,
reducing network use and speeding up information transmission.
Most of these are design problems. Even improved speed would result in a better experience
for people.
62. Problems a fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
• Reduced network traffic
Problems a fat client solves:
* The user can continue to interact (including simply viewing) while data is exchanged.
* The designer can customize and control the loading and transition experience between
contexts.
* Information can be presented in a partial, incremental, incomplete form, thus context can
be established while further information is retrieved. (Like a pan in a film, setting can be
established in advance of details.)
* The traffic between server and client can be reduced to data separate from the presentation,
reducing network use and speeding up information transmission.
Most of these are design problems. Even improved speed would result in a better experience
for people.
63. Problems a fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
• Reduced network traffic
→ DESIGN PROBLEMS (mostly)
Problems a fat client solves:
* The user can continue to interact (including simply viewing) while data is exchanged.
* The designer can customize and control the loading and transition experience between
contexts.
* Information can be presented in a partial, incremental, incomplete form, thus context can
be established while further information is retrieved. (Like a pan in a film, setting can be
established in advance of details.)
* The traffic between server and client can be reduced to data separate from the presentation,
reducing network use and speeding up information transmission.
Most of these are design problems. Even improved speed would result in a better experience
for people.
64. Problems a fat client causes:
Problems a fat client causes:
* Routing becomes the responsibility of the client-side script instead of the browser -->
deep-linking
* History management becomes the responsibility of the client-side script instead of the
browser --> back button
* Caching (what and for how long) becomes the responsibility of the client-side script instead
of the browser --> reusing previously-fetched data and templates to achieve improved
speed
* Improvements from the speedy transmission are eroded by computation within the client
i.e. instead of doing computation in an environment we can control (the server) we push it to
the client, which is notoriously out of our control.
These are technical problems. From a design perspective, these become trade-offs that are
“someone else’s problem”.
65. Problems a fat client causes:
• Routing
Problems a fat client causes:
* Routing becomes the responsibility of the client-side script instead of the browser -->
deep-linking
* History management becomes the responsibility of the client-side script instead of the
browser --> back button
* Caching (what and for how long) becomes the responsibility of the client-side script instead
of the browser --> reusing previously-fetched data and templates to achieve improved
speed
* Improvements from the speedy transmission are eroded by computation within the client
i.e. instead of doing computation in an environment we can control (the server) we push it to
the client, which is notoriously out of our control.
These are technical problems. From a design perspective, these become trade-offs that are
“someone else’s problem”.
66. Problems a fat client causes:
• Routing
• History
Problems a fat client causes:
* Routing becomes the responsibility of the client-side script instead of the browser -->
deep-linking
* History management becomes the responsibility of the client-side script instead of the
browser --> back button
* Caching (what and for how long) becomes the responsibility of the client-side script instead
of the browser --> reusing previously-fetched data and templates to achieve improved
speed
* Improvements from the speedy transmission are eroded by computation within the client
i.e. instead of doing computation in an environment we can control (the server) we push it to
the client, which is notoriously out of our control.
These are technical problems. From a design perspective, these become trade-offs that are
“someone else’s problem”.
67. Problems a fat client causes:
• Routing
• History
• Caching and garbage collection
Problems a fat client causes:
* Routing becomes the responsibility of the client-side script instead of the browser -->
deep-linking
* History management becomes the responsibility of the client-side script instead of the
browser --> back button
* Caching (what and for how long) becomes the responsibility of the client-side script instead
of the browser --> reusing previously-fetched data and templates to achieve improved
speed
* Improvements from the speedy transmission are eroded by computation within the client
i.e. instead of doing computation in an environment we can control (the server) we push it to
the client, which is notoriously out of our control.
These are technical problems. From a design perspective, these become trade-offs that are
“someone else’s problem”.
68. Problems a fat client causes:
• Routing
• History
• Caching and garbage collection
• Computation is outside of our control
Problems a fat client causes:
* Routing becomes the responsibility of the client-side script instead of the browser -->
deep-linking
* History management becomes the responsibility of the client-side script instead of the
browser --> back button
* Caching (what and for how long) becomes the responsibility of the client-side script instead
of the browser --> reusing previously-fetched data and templates to achieve improved
speed
* Improvements from the speedy transmission are eroded by computation within the client
i.e. instead of doing computation in an environment we can control (the server) we push it to
the client, which is notoriously out of our control.
These are technical problems. From a design perspective, these become trade-offs that are
“someone else’s problem”.
69. Problems a fat client causes:
• Routing
• History
• Caching and garbage collection
• Computation is outside of our control
→ TECHNICAL PROBLEMS
Problems a fat client causes:
* Routing becomes the responsibility of the client-side script instead of the browser -->
deep-linking
* History management becomes the responsibility of the client-side script instead of the
browser --> back button
* Caching (what and for how long) becomes the responsibility of the client-side script instead
of the browser --> reusing previously-fetched data and templates to achieve improved
speed
* Improvements from the speedy transmission are eroded by computation within the client
i.e. instead of doing computation in an environment we can control (the server) we push it to
the client, which is notoriously out of our control.
These are technical problems. From a design perspective, these become trade-offs that are
“someone else’s problem”.
70. Design problems a
fat client solves:
Let’s look again at the interaction design problems that a fat client can solve.
71. Design problems a
fat client solves:
• Continuous interaction
Let’s look again at the interaction design problems that a fat client can solve.
72. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
Let’s look again at the interaction design problems that a fat client can solve.
73. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Let’s look again at the interaction design problems that a fat client can solve.
74. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Let’s look again at the interaction design problems that a fat client can solve.
75. Maintain context
Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Let’s look again at the interaction design problems that a fat client can solve.
76. Maintain context
Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Let’s look again at the interaction design problems that a fat client can solve.
77. Maintain context
Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Establish context
Let’s look again at the interaction design problems that a fat client can solve.
78. Ajax → controls context
Ajax allows us to establish and maintain the context for the user, without jarring reloads.
BUT …
79. Ajax → adds complexity
Ajax also introduces all lot of technical complications.
This is complication that you as designer don’t have to think about, but creates a lot of extra
work for developers.
And that extra work might not be worth it. How can designers help developers be pragmatic
about when to use Ajax and when not to?
80. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
When we look at the problems that a fat client can solve, we can ask which one is the most
important?
-> Continuous interaction is the primary reason we use Ajax. We use it during form
validation, live chatting, commenting while watching a video
81. Most important
Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
When we look at the problems that a fat client can solve, we can ask which one is the most
important?
-> Continuous interaction is the primary reason we use Ajax. We use it during form
validation, live chatting, commenting while watching a video
82. Most important
Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
When we look at the problems that a fat client can solve, we can ask which one is the most
important?
-> Continuous interaction is the primary reason we use Ajax. We use it during form
validation, live chatting, commenting while watching a video
83. Continuous interaction
Continuous interaction is the primary reason we use Ajax. We use it during form validation,
live chatting, commenting while watching a video, performing a search.
84. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
So what benefit of Ajax is the least important?
-> Transitions between contexts
85. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Least important
So what benefit of Ajax is the least important?
-> Transitions between contexts
86. Design problems a
fat client solves:
• Continuous interaction
• Transitions between contexts
• Incremental loading
Least important
So what benefit of Ajax is the least important?
-> Transitions between contexts
87. New context? → Reload!
When the user switches to a new context, the page can just be reloaded.
89. “The cool kids are doing it!”
You might say:
BUT BUT BUT … all the cool kids are doing it! My product is also cool!
Maybe, but some of the cool kids still use page reload.
91. On github.com: a profile is a context, the repo file-browser is a context, and each pull
request is one context, with page reloads in between.
92. On github.com: a profile is a context, the repo file-browser is a context, and each pull
request is one context, with page reloads in between.
93. As we saw, Github is a collection of single-page apps, one per context, with page reloads in
between.
94. AJAX vs RELOAD?
So, when should you use Ajax and when should you use reload?
Let’s recap:
95. Limit your demand for Ajax
Limit your demand for asynchronous communication to only within the contexts that matter.
Only use it when you can afford it.
“Single-page apps” are often made as single-page apps for the wrong reasons. I have made
this mistake.
Where is our need for Ajax? -- at the interaction points.
96. Find the interaction points
Find the interaction points. Everywhere the user will click, type, hover or otherwise engage
with the interface.
For each, ask: what benefit vs cost does Ajax have at that interaction point? Can we afford the
cost? Where can we eliminate our need for Ajax?
97. Find the context boundaries
Know where the boundaries between contexts are, and communicate them to developers,
because these are important for designing the application architecture.
Using Ajax in at these interaction points give us the least benefit.
Lastly, for developers:
98. Does your framework
minimize your technical costs?
Does your framework help solve the design problems while minimizing the technical costs?
99. Single-page apps? YES: we can help our users maintain context so they can focus without
jarring interruptions. These means: use Ajax for each context, and each of those is its own
single-page app.
Monolithic apps? NO: or at least, they aren’t nearly as useful as they are technically hard, and
you should be very clear of the costs. You may get so much benefit, or have so many people
working in the problems, that you can overcome the costs. Your *entire web app* does *not*
need to be one single front-end app.
100. Single-page apps? → YES
Single-page apps? YES: we can help our users maintain context so they can focus without
jarring interruptions. These means: use Ajax for each context, and each of those is its own
single-page app.
Monolithic apps? NO: or at least, they aren’t nearly as useful as they are technically hard, and
you should be very clear of the costs. You may get so much benefit, or have so many people
working in the problems, that you can overcome the costs. Your *entire web app* does *not*
need to be one single front-end app.
101. Single-page apps? → YES
Monolithic apps? → NO
Single-page apps? YES: we can help our users maintain context so they can focus without
jarring interruptions. These means: use Ajax for each context, and each of those is its own
single-page app.
Monolithic apps? NO: or at least, they aren’t nearly as useful as they are technically hard, and
you should be very clear of the costs. You may get so much benefit, or have so many people
working in the problems, that you can overcome the costs. Your *entire web app* does *not*
need to be one single front-end app.