Archive for the ‘tabber’ Category

Nesting instict

Monday, March 20th, 2006

Nested tab interface

I’m running some tests tonight on my JavaScript tabber code… yeah, I would say it handles nested tabs.

Oh what tangled webs we weave…

Wednesday, March 15th, 2006

Because I didn’t want to foul up the namespace in my JavaScript tabber, I attached the tabber object directly to the DOM element it was controlling, then I had to add several “pointers” back and forth between the object and various DOM elements so they could get to each other without relying on any variables. When you look at it like this, it seems rather complicated:

Tabber diagram

I wonder if there are any issues with “memory leaks” due to IE’s faulty garbage collection… let me know if you notice anything.

Update: Hold the presses, I found a few more links. Some of these pointers are not used except when creating new elements to add into the DOM, so I can probably just switch those to use local variables. It shouldn’t matter, but with IE’s faulty garbage collection, who knows if it might cause problems.

Tabber diagram 2

Update :o h good god, the squiggly lines have taken over!

tabber-diagram3.png

Eliminating redisplay flashes in JavaScript

Thursday, March 9th, 2006

The Holy Grail in creating dynamic HTML is to have a page that works perfectly even when JavaScript is disabled. You want your page to be beautiful and dynamic, but you also want it to be accessible, search-engine optimized, and printable.

To make this happen you start with plain, semantic HTML, then you add a JavaScript layer to rework the page into something better:

JavaScript vs. No JavaScript

One problem with this technique is that your JavaScript must run after the HTML has been set up and rendered on the page, so a user with a slow connection might see something like this using my JavaScript tabbifier:

Animated simulation of HTML rendered then re-rendering using JavaScript

This is not too pretty, so obviously we want to make it stop.

Your first thought might be “I’ll just add a style to the content to make it hidden (CSS display:none), then my JavaScript will run and reveal it!” But that puts a big crack in our Holy Grail, because if you use CSS to hide the content, it will not be visible to users who do not have JavaScript.

Here’s the method I used:

  1. Add a class javascript-hide-me to the content you need to hide, but do not define that class in your CSS.
  2. Before the content, use JavaScript to define the CSS class. The easiest way to do this is by using document.write in the head section of the page, but you will have to directly modify the DOM if you are serving XHTML pages that use MIME type application/xhtml+xml.
  3. After the content has been transformed, use JavaScript to remove the CSS class and reveal the content.

Here are two examples, one that exhibits the flashing problem, and another that fixes it using the technique described above. Note that in order to see the flashing problem, you need a slow internet connection: I recommend throttling your connection using the excellent Charles Web Debugging Proxy.

Updates 2006-03-09

Welcome, Ajaxians!

Bobby describes an alternate technique in case you are serving XHTML pages that use MIME type application/xhtml+xml.

Steve Clay makes a valid point that we should check for DOM compatibility before writing the styles on the page.

Easier JavaScript object constructor arguments

Tuesday, March 7th, 2006

I stumbled across a nice technique when making my JavaScript tabifier.

Say you have a JavaScript object constructor:

function myObject() {
this.firstName = 'Patrick';
this.lastName = 'Fitzgerald';
}
var o = new myObject();
o.firstName = 'Lauren';
o.lastName = 'Fitzgerald';

But you want to make it easy to override the properties, so you pass them in as arguments to the constructor:

function myObject(firstName,lastName) {
if (firstName) { this.firstName = firstName; }
else { this.firstName = 'Patrick'; }
if (lastName) { this.lastName = lastName }
else { this.lastName = 'Fitzgerald'; }
}
var o = new myObject('Lauren','Fitzgerald');

Fine and dandy, but what if you start adding more properties? Suddenly your object constructor is getting complicated, ugly, and confusing:

myObject(firstName,lastName,phone,ssn,hairColor);

Instead set up all the default values for your object properties, and use a single argument to override the values:

function myObject() {
this.firstName = 'Patrick';
this.lastName = 'Fitzgerald';
this.phone = '';
this.ssn = '';
this.hairColor='';
for (var n in arguments[0]) { this[n] = arguments[0][n]; }
}

By adding one line to your object constructor, you have given the user the flexibility to change any of the default parameters. Furthermore, they can specify the parameters in any order, and leave out the ones they don’t want to change.

Compare the two:

var o = new myObject('Lauren','','','','brown'});
var o = new myObject({firstName:'Lauren',hairColor:'brown'});

This also gives the user the ability to add custom parameters or even methods to the object, all with a single call to the object constructor.

See also: Using JavaScript objects for function arguments with default values

Italian tabification

Monday, March 6th, 2006

My JavaScript tabifier has reached the shores of Italy. Here is a blog post translated to English:

Small appendix to the post of Alexander Fulciniti on the return of the tab in order to signal this Javascript tabifier. Draft of a script that indeed renders the creation of an interface based on these elements simplest. Enough to follow the three steps suggested from the author, to structure the markup following one series of rules base in order then to dedicate itself more profitablely to the personalizzazione of the styles.

I couldn’t have said it better myself.

JavaScript tabifier

Thursday, March 2nd, 2006

Damn, was I beaten to the punch?

A while back I was working on an automated tabifier using JavaScript, then this popped up today in the popular page in deli.icio.us: Link

I shouldn’t post unfinished code, but damn it, I think mine is better! :-)

My tabs are completely CSS controlled, they look great without JavaScript and the page always prints (I think a lot of DHTML developers do not take into effect that a page will be printed).

Anyway, check it out here: JavaScript tabifier

If you like it please contact me – with enough encouragement I might continue this project.