Tuesday, December 16, 2008

Google is Visually Impaired

What real difference does it make if you use HTML tables instead of CSS to control the layout of your Web page? If you're a professional Web designer you probably already know, and you can stop reading now. Thanks for stopping in. For the rest of you, the title of this article is a hint.

The truth is, HTML tables are a lot easier to control. I can control every aspect of the appearance of a table using very little markup, and as a bonus it looks pretty much the same across all the major browsers. And I'm not even a Web developer. This seems like an easy choice. I don't want to have to learn about liquid layouts. Absolute positioning sounds like a good thing, but then I have to learn about something called the box-model hack? No thanks. Tables are fine. Tables are easy.

But what about Usability? I remember taking a course in college about that, and reading this really cool book by a guy named Don Norman called The Design of Everyday Things. It's about how simpler design is better, and that's why the iPod is so awesome. That goes right along with designing Web pages with tables. They're simple, right?

Not so fast. I also remember Norman saying something about how design should be simple from the perspective of the user. There's a trap here that's easy to fall into. You don't want to make a design decision base on how easy it is to implement, you want to make the choice based on how easy the design is to use. We've already established that tables are a lot easier on the developer, but how could they make a difference to the user? They're just reading the information off the page, right?

Well, most of them are. Some people have to use screen readers, and screen readers don't read tables in the same order as they read the elements in a CSS layout. It's a really small percentage of internet users, though, and you can't even find accurate statistics because all of the studies lump everyone with a disability in to one big group in order to inflate the numbers. It's really small, something like 10%* of internet users are using some sort of assistive technology like a screen reader. So for some small percentage of internet users, probably less than 10%, using a table-based layout will provide a less than ideal user experience.

Visual impairment is really random, though, so that means that about 10% of virtually any of internet users are using some sort of assistive technology like a screen reader. So for some small percentage of internet users, probably less than 10%, using a table-based layout will provide a less than ideal user experience. Can you really afford to turn away a random 10% of your potential Web audience? If you can, keep reading.

Google is visually impaired. (Let that sink in.)

Even if you don't care about users with accessibility issues (and you should), there's one user that everyone should care about. The web crawler that Google uses to scan the internet and index your site can't really see the pages. It reads them just like a screen reader would. That is, it reads pages from top to bottom, just like the screen readers are programmed to. They can't tell the difference between a table used for layout and a table used to hold tabular data, so they treat them both the same. HTML tables are meant for tabular data, so that's how screen readers and the Google web crawler read them.

Table-based layout is quick and easy. CSS layouts are complicated and hard. Does it really matter if you choose tables? Yes, more than most people realize.

* Really? Ten percent? No, I can't back that up. Even if it's only 2%, though, Google is still in that 2%.

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