Robust Web Design - part 4 -last

Beware of java programmers in guise of java script programmers

Will you ever use a Japanese interpreter for your trip to China? Just because things appear the same doesn’t mean they are the same. One may understand things, but is it sufficient? I personally feel that there are two styles of programming, sniper style and landmine style. One has precision and the other has visibility. Good programmers use precision, they know what to do and the impact of what they are doing. Others still in the learning cycle, try to apply intution or make assumption. Learning languages helps, learning the purpose of the language is saviour. Ever heard about the ‘Golden hammer anti-pattern’? It is important to know what to use and where to use it.

Java script shares a lot in common with Java, human minds being very adaptive at least perceive so. The reality is different. It is easier for a Java programmer to master java script. All I am interested is, if any effort is invested in that direction.

Philosophical differences between Java and Java script:

1. Java is static typed, java script is dynamic; there is no type checking in place so use of proper naming convention is vital.
2. Java is application language with support for class invariants. Java script was designed to live in web browsers (I know jdk 6, FX and desktop support, but please…). Web browsers are not supposed to support business invariants, they support view (V of MVC). If someone uses Math library in java script, take him into custody.
3.Java doesn’t support closures (not yet till jdk 6). Java script does. In case, you are wondering, Closure is just a set of statements that can be passed here and there (as parameter). It is just a different style of doing things, you know!!
4.Java is inherently object oriented most of the time with a central control structure. Java script on the other hand is functional and event-driven.

One symptom of java programmer not doing his homework, is use of ‘==’/’!=’ in place of ‘===’/‘!==’.

Namespace contamination horrors

A good java script programmer tries to keep namespace contamination to a minimum by using object based style. ‘Revealing module pattern’ and ‘Singleton’ are some examples. We can also get huge performance benefits by reusing objects than recreating them. Magic numbers in code can be kept to a minimum using the above. In fact a good piece of work also show cases, cross browser compatible event handling.

Some references: On java script patterns

We can achieve similar things in CSS by using a unique template id and referring to it in all selectors. This non-semantic declaration is worth its cost. When programming in a large team, these decisions become important.

The class of web 2.0: IE, Mozilla, Opera…

Each of us is unique, that aspect makes ‘each’ of ‘us’. So are browsers. Some prominent aspects I left of earlier are summarised here

Event model

W3C standard even model speaks of three phases capture, target and bubble. Not all browsers support this. So there is a need to hack into the event model and support the least common factor. A custom event model should also prevent function overriding, (usually happens when two different functions are tied to the same event)

Dom model

Not all browsers support Dom functions uniformly. We need to have a custom common wrapper library for the most useful ones and refer to the library. These assets can be reused across assignments.

Xslt wonder

Java script is not the only way to present a view. Certain sections of the user community/application may be reluctant to use scripts. Xslt is the answer for such. It is rich specification with support for reg-ex as well!

AJAX, JQuery, DOJO and others

We discussed the group of java script dissidents; as the world exists we also have a section of aficionados. These guys are those who enjoy the privilege of huge broadband, fast processors and humungous main memory when compared to the past era (read 4 years ago). Writing our own scripts and testing for cross browser compatibility is painful. Why not ask someone else to help us out here? Dojo, JQuery, YUI from yahoo, GWT from Google, JMaki and several others have been targeting these goals.