AJAX - The Complete Reference

PART II

Chapter 5: Developing an Ajax Library 221

Function Description Example

$$ Takes a CSS string as an

argument and returns an array

of matches.

var nodes = $$('a.nav');

$A Takes an object and converts

it into an array. If passed a

string, each character gets its

own index. If passed a DOM

NodeLists, it changes it to an

array.

var someNodeList = $('colors').

getElementsByTagName('option');

var nodes = $A(someNodeList);

$F Returns the value of a given

form element.

var name = $F('firstname');

$H Creates a hash. var h = $H({ name: 'Prototype',

version: 1.5 });

$w Splits a string into an array

using space as a delimiter.

var colorArray = $W('Red Orange

Yellow Green');

getElementsByClassName Returns the elements that

match the given class name.

Starts at document if no start

node is specified.

var links =

document.getElementsByClassName

('nav', $('headerDiv'));

Try.these A simplified tr y/catch. In

this case, you pass multiple

functions and the code will tr y

to execute each one until one

succeeds. That one will be

returned.

Try.these(

function(){return new

XMLHttpRequest(); },

function(){return new

ActiveXObject(

"Msxml2.XMLHTTP.6.0" ); },

function(){ return new

ActiveXObject(

"Msxml2.XMLHTTP.3.0"); },

function(){return new

ActiveXObject

(" Msxml2.XMLHTTP"); },

function(){ return new

ActiveXObject(

"Microsoft.XMLHTTP"); }

);

TABLE 5-9 Sample of Useful Prototype Facilities (continued)