Tanzim Saqib on .NET discovery

Unlike .NET languages or any other compiler languages, JavaScript interpreter can not optimize switch block. Especially when switch statement is used with different types of data, it's a heavy operation for the browser due to conversion operations occur in consequences, it's an elegant way of decision branching though.

In one of my earlier posts, I talked about DOM element accessing in a loop but forgot to talk about a very common, yet performance issue in AJAX. We often use code like the following:

var items = []; // Suppose a very long array 
for(var i=0; i<items.length; ++i)
    ; // Some actions

var items = []; // Suppose a very long array 
var count = items.length;
for(var i=0; i<count; ++i)
    ; // Some actions

Less use of "var" can result into wrong calculation as well as mistake in logic control. And also JavaScript interpreter finds it hard to determine the scope of the variable if var is not used. Consider the following simple JavaScript code:

function pageLoad()
{
    i = 10;
    loop();
    alert(i);   // here, i = 100
}

function loop()
{
    for(i=0; i<100; ++i)
    {
        // Some actions
    }
}

Here you see, the loop uses the variable i used before in pageLoad. So, it brings a wrong result. Unlike .NET code, in JavaScript variables can go along with the method calls. So, better not confuse the interpreter by using more "var" in your code:

function pageLoad()
{
    var i = 10;
    loop();
    alert(i);   // here, i = 10
}

function loop()
{
    for(var i=0; i<100; ++i)
    {
        // Some actions
    }
}

I, Tanzim Saqib  do work as Developer at the AJAX king "Pageflakes.com". I've spent half of my life on software and worked in many projects ranging from Banking solution for CitiBank, HSBC, Wells Fargo etc. to Personalized Start Page. I love twisting latest Microsoft technologies. In my spare time I enjoy National Geographic channel, writing articles and blogging.

Drop few lines: me@TanzimSaqib.com
Original Homepage: http://www.TanzimSaqib.com