AJAX - The Complete Reference

222 Part II: Applied Ajax^

look carefully at the examples presented in the table, you can see the reason for the major

criticism that people have with Prototype: it has extended or even overridden core

JavaScript features. For example, the stripTags() method has been added as a prototype

to all strings in JavaScript. This is certainly helpful and explains greatly why the library is

named the way it is. However, there is a dark side here. What happens if another script or

library in the page expects JavaScript types or methods to act in their default manner?

Obviously, there is great potential for conflict.

NNOT EOTE Critics of Prototype are quite vocal in pointing out that the library often does not play well

with others. Most often such conflicts arise due to the overriding and extension of various core

JavaScript facilities. However, in some cases it is simply the fact that everyone wants to use the

$() function in a different way.

Function Description Example

escapeHTML (string) Converts XHTML tags

into escaped character

entities.

var tab = "<table><tr><td>TEST</

td></tr></table>";

var tabesc = tab.escapeHTML();

clear (array) Removes all items from

an array.

arr.clear();

evalJSON (string) Evaluates a JSON string

and returns the object.

Accepts an optional

sanitize parameter that

won’t do the eval()

if it finds any malicious

content.

var obj = "{name:Alex, age:2}".

evalJSON(true);

first (array) Returns the first element

of an array.

var firstItem = arr.first();

indexOf (array) Returns the index of item

the val passed into the

functions. Similar to the

indexOf() for strings.

var index = arr.indexOf("Giants");

parseQuery (string) Splits a quer y string

into an associative array

indexed by parameter

name.

var query = "a=123&b=456&c=789";

var queryObj = query.parseQuery();

stripTags (string) Returns the string with

all HTML tags removed.

var tab = "<table><tr><td>TEST</

td></tr></table>";

var tabesc = tab.stripTags();

without (array) Returns the array without

the values indicated.

var cleanArray = oldArray

.without("Dodgers", "Padres");

TABLE 5-10 More Prototype Utilities