Accelerated DOM Scripting with Ajax, APIs, and Libraries

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Jonathan Snook, Aaron Gustafson, Stuart Langridge, and Dan Webb

"Accelerated DOM Scripting with Ajax, APIs, and Libraries"

Here??™s an example that demonstrates the relationship between everything:
function ObjectA(){ /* stuff */ }
ObjectA.methodB = function ()
{
// arguments now has 6 elements:
alert($A(arguments)); // 1,2,3,4,5,6
}
var bound = ObjectA.methodB.bind(ObjectA, '1','2','3','4');
bound('5','6');
CHAPTER 3 n OBJECT-ORIENTED PROGRAMMING 76
Using call or apply, especially as shown here, can make your code look cleaner and more
readable.
Applying a Function to a Collection
A handy way to use callbacks is to apply a function to a series of elements within an array or
object (which are very similar in functionality). The ability to receive functions as parameters
enables you to apply a function to any and all items within a collection.
Here??™s a great example taken from jQuery (http://jquery.com):
$("p").each(function(){
this.innerHTML = this + " is the Element";
});
Despite the brevity of this code example, there??™s actually a lot happening here. First, a
function called $() takes in a string parameter. In this case, it finds all

elements on the
page. In other words, $("p") returns a collection of paragraphs in the document. Then, the
each() method will apply a function to each item in the collection (in this case, the innerHTML
of each paragraph tag will be replaced with the string).
You can create your own example now that will parse through your own special array:
function SpecialArray(arr)
{
this.

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Schaum's Outline of Principles of Computer Science (page 274) Practical Reporting with Ruby and Rails (page 287) Foundation Flex for Designers (page 15)

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Jonathan Snook, Aaron Gustafson, Stuart Langridge, and Dan Webb

"Accelerated DOM Scripting with Ajax, APIs, and Libraries"