[TSE] Building Modern Web Applications with Mike Stenhouse
Mike Stenhouse is the creator of the CSS Framework we use in AppFuse1. Mike is going to talk about the tools he uses to develop web applications. Mike works solely on the front-end, no backend work.
"In 2007 we’ll witness the increasing dominance of open internet standards. As web access via mobile phones grows, these standards will sweep aside the proprietary protocols promoted by individual companies striving for technical monopoly. Today’s desktop software will be overtaken by internet-based services that enable users to choose the document formats, search tools and editing capability that best suit their needs." -- Eric Schmidt, CEO Google
Web Standards is a methodology and philosophy, not just valid CSS and XHTML. The main philosophy behind web standards is progressive enhancement. The methodology behind web standards is a 3-step process.
- Figure out what the content means
- Code the HTML accordingly, ignoring the design
- Then write your CSS to realise the design
X/HTML is where you get most of your benefits from. It should be content only, nothing else. If your content and XHTML sucks, CSS is probably not going to be able to help a whole lot. HTML vs. XHTML have small syntax differences, the main differences show up with the mode of the doctype. HTML 4 Strict, XHTML Transitional and XHTML Strict are all good. HTML 4 Loose sucks.
HTML is the skeleton and isn't as easy as people think it is. Tables and nested tables are some of the worst offenders of bad HTML. When people move from table-based layouts to standards-based layouts, it's usually a disaster because of meaningless classes on div tags. A lot of times, adding classes to HTML elements is completely meaningless. The less classes and ids, generally the better. By removing classes, your HTML becomes much more readable (save for input tags and such).
This is what's called semantic HTML. It has nothing to do with the Semantic Web. Using HTML for what it's designed for. Headings are in order, paragraphs, lists, inputs, labels, fieldsets. Tables are used only for tabular data.
To write semantic HTML, use the following guidlines:
- Look at your content and figure out its meaning
- Think of the document outline mode in Word -the headings are used to navigate
- Group form elements and work out what order they should be filled in
- If it’s too tricky there might be a problem with the design
Using these guidelines will help you write cleaner code. The CSS Zen Garden is a poor example of semantic HTML - there's just too many classes. You should try to push classes and ids upwards. For example, you can convert the following HTML from:
<ul> <li><a class="navlink" href="x"> <li><a class="navlink" href="y"> <li><a class="navlink" href="z">
<ul class="nav"> <li><a href="x"> <li><a href="y"> <li><a href="z">
The first example only allows you to style with "a.navlink", whereas the 2nd gives you more elements to style (ul.nav a, ul.nav, ul.nav li).
Another suggestion is to use multiple classes on your HTML elements. <body class="order final sales"> can be controlled with body.sales, body.final and body.order.final CSS classes. CSS class names should be almost like metadata - they should relate more to the content to the design.
By using web standards-based design, you get the benefits of debugging (W3C Validator). In addition, you get SEO benefits from good HTML. If you use proper semantic HTML, machines can make better sense of your HTML. Headings are one of the most important things for SEO. It's amazing how simple this stuff is and how few people understand it.
Microformats are a way of adding metadata to your HTML. They basically say to use classes, rels and refs, and use them in a specific way. The Semantic Web community has recently started forming ties with the microformats community. A few uses are currently in existence: hCard, hReview, hCalender, hResume, XFN, XOXO, rel-directory, rel-pavatar, rel-nofollow, rel-tag and xFolk.
To conform to a microformat, you simply need to add add certain classes to your existing markup. For example, here's an address in hCard format:
<div class="box vcard"> <h3>Contact Details</h3> <a class="fn url" href="ttp://adactio.com/"> <span class="given-name">Jeremy</span> <span class="family-name">Keith</span> </a> <p class="adr"> <span class="street-address">57/58 Brunswick Road</span> <span class="locality">Hove</span> <a class="postal-code" href="http://maps.google.co.uk/maps?q=bn3+1dh" title="map">BN3 1DH</a> <span class="country-name">England</span> </p> </div>
If you feed this into Technorati, it can give you back a vCard. It can also work by specifying a URL that contains HTML with this microformat.
Even Bill Gates said "We need microformats". They're definitely starting to get a lot of traction. The beauty is they're very simple to use and implement.
What's important about CSS is it allows you to redefine how your HTML elements behave and display on a page. Firefox actually uses CSS (including some CSS 3.0 stuff) to control how HTML renders. With CSS, you can extract your design from the HTML. It's the icing on the HTML cake.
CSS allows you to separate the front from the back. It can very useful for designers and developers. Developers do the HTML, designers do the CSS. The CSS Zen Garden is the best example of how powerful CSS is.
CSS allows you to retask-content. For example, supplying a different CSS file for printing is a great use. There's also support for mobile devices and projectors, but they're not as well supported.
CSS allows you to define your display once and reuse more. DRY for HTML. You can even get re-use between sites by using "modular CSS". Mike generally breaks his CSS down into groups using @import:
@import url("tools.css"); @import url("typo.css"); @import url("forms.css"); @import url("tables.css"); @import url("layout.css");
Other breakdowns: site sections, color, old browsers vs. new browsers and layout (CSS Framework). Basically, use a different stylesheet to separate these different breakdowns.
Mike invented the CSS Framework as a "set of standard naming conventions for the HTML and an example set of layout stylesheets".
Hacks for the different browsers: the only one that Mike uses regularly is "* html" for IE. He generally applies "height: 1%". Occasionally he needs \ for IE 5.x.
w\idth: 50px; width: 40px;
The final hack is to put your IE-specific rules in ie.css, but Mike's not a big fan of it.
Rules of thumb to avoid browser-compatibility issues:
- Avoid margins and padding on elements with a width
- Use % font-size on the body and ems for everything else
- Avoid PNG and alpha transparency
- Avoid too much styling on form elements (can be a nightmare to do cross-browser)
IE7 fixed the * html parsing error so filter doesn't work in IE7. They haven't fixed "hasLayout" or conditional comments. "hasLayout" is a bug in IE that adds padding around list elements whenever they have any CSS styles applied to them. I'm sure there's more too this, but I didn't get a chance to write it down.
Triggering hasLayout cures similar problems to height: 1% in previous versions. You can manipulate programmatically using object.currentStyle.hasLayout.
Conditional comments are still a problem. Mike likes it because it allows you to put all your IE hacks in one place. He doesn't like it because it requires you keep an extra things in your head.
The first thing that brought back Ajax is "DOM Scripting". DOM Scripting is methods for accessing and modifying the DOM. The DOM is an HTML page represented as a tree of objects.
History: DOM0 was not a standard. DOM1 is a standard for navigation and manipulation. DOM2 is XML and events (onclick, onblur, etc.).
- XmlHttpRequest object
- Flash Remoting
Mike is using applets on a project right now for heavy visualization. They use Ajax with applets so it doesn't unload the VM and they're calling it "AppleJax".
Frameworks can help you get around a lot of the issues with Ajax. The problems with frameworks is there are so many. A few of the best: Dojo, Prototype, YUI, MochiKit, Moo Tools and jQuery. Mike's favorite is jQuery.
Dojo is great, but almost does too much. Mike is afraid to use it because he doesn't understand how they do some things.
- Devilishly clever
- Application-like functionality in the browser
- Includes stuff like client-side storage
- Not much documentation
- Black magic
- The full weight of Yahoo! behind it
- Extremely well documented
- Lacking in sex-appeal
- Can get very heavy
- Modeled after Python
- Quite heavy
- Highly rated but hasn’t experienced the sort of adoption the other frameworks have seen
- Built into Rails (the main reason Mike used it)
- Good Ajax
- Quite heavy, especially with Scriptaculous
- Dispersed documentation but readable source code
- Missing some basic helpers (addressed by Low Pro)
- Very compact
Mike mentions Moo Tools because friends have recommended it that are "in the know".
- Uses CSS syntax
- Perfectly suited to progressive enhancement
- Functional design
- Well documented
- Basic Ajax
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A better solution is:
onready is a better way to do window.onload as it will fire as soon as the HTML has come down. Hijax embraces this idea. The approach is as follows:
- Make a rock-solid, Web 1.0 app
- Good, old fashioned GETs and POSTs that will work in any browser and on any platform
- Just HTML styled with CSS
Back to Eric Schmidt's quote. If you use "progressive enhancement", it's an excellent way to leverage web standards. The better the browser, the better the experience.
1. At the end of his talk, Mike mentioned that he got invited to this conference because we use the CSS Framework in AppFuse. Cool!
After Mike's talk, I walked up and introduced myself. I thanked him for the CSS Framework and we chatted a bit about his talk. I really like his recommendations of progressive enhancement (or Hijax) and plan to use it a lot more when developing UIs. Mike was an excellent speaker and one of those guys you instantly want to have a beer with.
Posted by Aleksandar Pavic on December 11, 2006 at 06:22 AM MST #
Posted by Mike Stenhouse on December 11, 2006 at 08:29 AM MST #