Developer/Designer Notes

Archive for May, 2007

CSS background-position and backgound-attachment

Posted by Kiran Mova on May 18, 2007

I wish the definition of values was more straightforward. But well, how does one define something that fits everyones perception. Here is what worked for me and hopefully I am going to remember this right. Of course, I got this from Eric Meyer on CSS.

background-position : the values are ‘fixed’  and ‘scroll’. ‘fixed’ is fixed relative to browser and not on the element on which the attribute is defined. When the image is ‘fixed’, it will be placed relative to top left corner of browser. The catch is that only the portion of the image that overlaps the element on which it is defined will be visible. Which explains why my sort images were disappearing from ‘th’, when I set the attribute to fixed. So don’t use fixed when the images are small and have to be near the element to which they belong.

background-position: The  valid keyword value combinations are : [top|center|bottom] [left | center| right]. Check this values at CSS Reference from W3C. Now what confused me was that the values are supposed to be xpos and ypos. But the keywords seem to specify y value before the x value. (Well, it works if specify the x-keyword before y-keyword.)

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Usability Testing – what? when? how?

Posted by Kiran Mova on May 9, 2007

Designing a good user interface for Web Applications is hard because :
– The web designer doesn’t know how a specific user will interact with the system
– The user is driven by his goals and not how the system is designed
– Users may not spend time to get the idea of how system works, they would try to make snap decisions to get there things done.

Look at Ben Hunt’s article on web design process

Usability.gov describes usability as –

usability refers to how well users can learn and use a product to achieve their goals and how satisfied they are with that process. Usability, as defined by Joseph Dumas and Janice (Ginny) Redish, means that people who use the product can do so quickly and easily to accomplish their tasks. Usability may also consider such factors as cost-effectiveness and usefulness.

Usability Testing is a must while developing a web site. Though I want to argue that if we are developing a web site that has a similar interface like the one already available in the market and the one which people have been using. For example, if i am developing a new web mail application, and if I model my application similar to yahoo, do I need to spend time on usability testing? Users are familiar with what to expect from a web mail service.

Of course, I can add a few new features here and there that make my web mail different from those available in the market. I could use a system in the back end that can monitor to see if the users are really using this new feature and have a mechanism to identify if it has been helpful. (Building such intelligence into the system is obviously the hard part..)

And for this reason, still usability tests are better performed in person. Recruit the target audience and watch them as they use the features..

This link on Usability Testing from University of Texas, Austin is very informative and goes on to say – “start performing the usability tests, which is 4 to 8 weeks prior to the system going live.” This assuming that the design is close to being accepted (which is true in most of the cases.) However as I read in some place else, it is better to perform usability testing in different phases. If the system is not live, use a paper prototype and devise a test plan to get some early feedback. Especially if the site is very visual or content rich, go out there to find out if the icons/content hierarchy is intuitive to the audience.

Need to learn more – Check Jakob Nielsen’s site

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