Ralph’s son Henry

I ran into a problem where I wanted one single array of all of the pages list items’s where the only thing they had in common was that the parent parent node has a class name of  ”tabs”. Here is a slimed down version of what I had: 

<div main="main">
  <div class="tabs">
    <ul>
      <li>One</li>
    </ul>
  </div>
  <div class="tabs">
    <ul>
      <li>Two</li>
    </ul>
  </div>
</div>

One solution would be to find all of class=”tabs” then build an array, for each instance of tabs. Then combine them together. That is completely viable but YUI provides a better way, getElementsBy();

var listItems = YAHOO.util.Dom.getElementsBy( function() {
  return el.parentNode.parentNode.className == "tabs";
}, 'li', document.getElementById('main'));

It takes three params, 1) a function for each tested object to pass 2) an optional tag name to search for 3) a scope selector. Both 2 and 3 are optional.

Saves the day.

In my particular case, adding extra markup on the list item wasn’t possible, and YUI really saved me a ton of time. Nice work YUI.

Chris has a post on the company blog with more info. Illustration by Dennis Hengeveld.

At work we have a lot of css files. 79 to be exact. The code itself is organized pretty well and I am very happy with that aspect of it. There is however one thing that I hate. That is just about any use of id’s as a css selector.

Current wisdom suggests you should use class names for elements on the page that are repeated and IDs where an element has only one instance. At first glance and on a small scale that make sense. On a large scale and after a close look problems start to arise.

Here is a sample of what I wanted to write:

.my-class p {}


But I ran into an issue because at a higher level the in that container was already specified as:

#some-class .some-other-class p


The problem is that ID’s have a high level of inheritance and cannot be overridden without the use of !important or the same or higher level of specificity The solution is simple but makes my code look terrible. So now I have:

my-class { }
.my-class a { }
#some-class .some-other-class .my-class p { }
.my-class .date { }


After I figured this out I started to wonder.. “What is the value of using and ID vs a class name?” Does it make your website faster? Better? More valid? What should I even consider? What would happen if I used class names exclusively for css, and ID’s specifically for javascript? Here are two reasons why I think you should:

1. One of the goals for an modern web developer is to completely separate the 3 main aspects of his/her code. Specifically the structure, presentation and behavior. However anyone who does this using a mix of ID an class names has unknowingly created a dependancy between their behavior and their presentation layer. That means that changing an Id or class name in the css has the potential to break javascript or vise versa.

2. If all css selectors are written with class names, no one style has inheritance over any other rule. The style sheet cascades as it was designed

Overkill? Perhaps, but food for thought.

I went to start up school last weekend and I learns a few things:

1. How old I am? I am only 31, but I really felt like the one of the old guys in the crowd. (this doesn’t include the unix-beard types, who are really old). It was even brought up a couple of times how the average founder age that YCombinator funds is 25 years old. I suppose that they throw that around so young people with great ideas don’t get discouraged, but it just made me feel old.

2. That there are still good people doing good things. Paul Graham, who I have known of gave a great talk on the basis for starting a good company. The premise was that if you act like a non-profit, in that you genuinely try to solve peoples problems, you are well on the way to success. I like this kinda of propaganda, and against the contrast of the other VCs and talk of millions of dollars it was refreshing.

3. What a good speaker Jeff Bezos, CEO of amazon is. He was articulate, direct and polished and never once used a “marketing approved” company line. He was patient with hard questions and in two instances quick to say, “I don’t know.” The more time I spend in business, the more I realize that saying “I don’t know” gets harder and harder, the higher up the corporate ladder you are.

Looking forward to next year.

Videos of the conference here:
http://omnisio.com/startupschool08