Prototype JavaScript Framework

Contents
The Ajax object
Problems
See also
References
Bibliography

Prototype
Original author	Sam Stephenson
Developer	Prototype Core Team
Release	February 2005;21 years ago (2005-02)

The Prototype JavaScript Framework is a JavaScript framework created by Sam Stephenson in February 2005 as part of Ajax support in Ruby on Rails. It is implemented as a single file of JavaScript code, usually named prototype.js. Prototype is distributed standalone, but also as part of larger projects, such as Ruby on Rails, script.aculo.us and Rico. document.getElementById("id_of_element").style.color="#ffffff";

The $() function reduces the code to:

$$("a.pulsate").each(Effect.Pulsate);

The Ajax object

edit

In an effort to reduce the amount of code needed to run a cross-browser XMLHttpRequest function, Prototype provides the Ajax object to abstract the different browsers. It has two main methods: Ajax.Request() and Ajax.Updater(). There are two forms of the Ajax object. Ajax.Request returns the raw XML output from an AJAX call, while the Ajax.Updater will inject the return inside a specified DOM object. The Ajax.Request below finds the current values of two HTML form input elements, issues an HTTP POST request to the server with those element name/value pairs, and runs a custom function (called showResponse below) when the HTTP response is received from the server:

Ajax.Request=Class.create(Ajax.Base,{ // Override the initialize method initialize:function(url,options){ this.transport=Ajax.getTransport(); this.setOptions(options); this.request(url); }, // ...more methods add ... });

The framework function Object.extend(dest, src) takes two objects as parameters and copies the properties of the second object to the first one simulating inheritance. The combined object is also returned as a result from the function. As in the example above, the first parameter usually creates the base object, while the second is an anonymous object used solely for defining additional properties. The entire sub-class declaration happens within the parentheses of the function call.

Problems

edit

Unlike other JavaScript libraries like jQuery, Prototype extends the DOM. There are plans to change this in the next major version of the library.

In April 2010, blogger Juriy 'kangax' Zaytsev (of Prototype Core) described at length the problems that can follow from monkey patching new methods and properties into the objects defined by the W3C DOM. These ideas echo thoughts published in March 2010 by Yahoo! developer Nicholas C. Zakas They have been summarized as follows

Cross browser issues: host objects are not subject to rules, non-compliant IE DOM behavior, etc.
Chance of name collisions
Performance overhead

By 2008, specific issues with using DOM-extension methods in older versions of Prototype, combined with newer versions of current browsers, were already being documented. Rather than adding new methods and properties to pre-existing 'host' DOM objects such as Element, like element.hide(), the solution to these issues is to provide wrapper objects around these host objects and implement the new methods on these. jQuery is such a wrapper object in the library of that name.

References

edit

kangax (5 April 2010). "What's wrong with extending the DOM". Retrieved 6 April 2010.

↑ Resig, John (26 March 2008). "getElementsByClassName pre Prototype 1.6". Retrieved 6 April 2010.

Bibliography

edit

The Ajax object

Problems

See also

References

Bibliography