Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: ColdFusion, Adobe Flex, Machine Learning

ColdFusion: Article

An Introduction to AJAX and Taconite

Yes, it works

AJAX stands for Asynchronous JavaScript and XML. The core of AJAX is the use of the XMLHttpRequest() object to communicate with server-side scripts. It can send and receive information in XML, HTML, and plain text.

The "Asynchronous" part means the client can communicate with the server without page refreshes. This allows you to update portions of a page based upon user events and is what allows developers to create Rich Internet Applications (RIA) using existing technologies.

Introducing Taconite
Taconite is a framework that simplifies the creation of AJAX-enabled Web applications. It's a very lightweight framework that automates the tedious tasks related to AJAX development, such as the creation and management of the XMLHttpRequest object and the creation of dynamic content. Taconite can be used with all modern Web browsers (Firefox, Safari, IE, Opera, and Konqueror, to name a few) and can be used with any server-side technology, including Java EE, .NET, PHP, ColdFusion or any language that lets you return XHTML.

The XMLHttpRequest object is not officially part of any Web standard, including W3C standards. Hence, the W3C created the Document Object Model Load and Save specification. Taconite is based on the concepts behind the W3C's Document Object Model Load and Save specification.

The heart of Taconite is a parser that converts normal (X)HTML code into a series of JavaScript commands that dynamically create the content on the browser. This parser allows the developer to write content in a way that is natural - as (X)HTML. You no longer have to crowd your pages with a slew of document.createElement and document.appendChild commands to dynamically create new content. The resulting JavaScript is evaluated by the browser's JavaScript engine to produce the content specified by the (X)HTML. All you need to do is make sure that the content being generated is valid XHTML. That means single tags must be self-closing, attributes need to be in quotes, special characters need to be escaped and attribute minimization must be avoided (i.e., nowrap should be nowrap="nowrap").

The Taconite custom parser is implemented as a set of JSP custom tags that can be used in any Java servlet container, or as a client-side JavaScript library, meaning it can be used in conjunction with virtually any server-side technology.

Taconite focuses on removing the tedious task of writing large amounts of JavaScript to dynamically update content on a Web page. Unlike some frameworks that try to invent a new way of sending request data to the server, Taconite relies on the tried-and-true name/value pairs either embedded within the query string of a GET request, or tucked safely into the body of a POST. The client-side library even automates the creation of the name/value query string. All you need to worry about is telling Taconite what values should be sent to the server, and it takes care of the rest.

Since the JavaScript is created by the parser based on the HTML you specify, you don't have to worry about dealing with browser JavaScript incompatibilities. The parser takes care of them all for you. All you need to do is specify the dynamic content as HTML, and the parser does the rest.

InnerHTML Avoided
Many of the currently available AJAX frameworks rely on the innerHTML property to dynamically create and update content on the Web page. Taconite completely avoids the use of innerHTML.

The main problem with innerHTML is that it's non-standard. It is not specified by any W3C recommendation, although it is supported by most of today's browsers. Another problem with innerHTML is that it really only applies to HTML documents, not XHTML documents, which is what the industry is moving to. As browsers move to better, more strict support for XHTML documents, they may not support innerHTML due to its non-standard nature.

Coming as a surprise to absolutely nobody, the innerHTML property has its own browser-to-browser quirks. For example, IE won't allow the innerHTML of a <table> to be appended. So, if you want to append one row to a table using innerHTML, you'll have to reproduce the entire contents of the table tag, with the one new row added at the end. That's just a waste of processing time and bandwidth.

Using the innerHTML property doesn't lend much control when it comes to placing the new content. For instance, if you want to insert a table row between two existing table rows using the innerHTML property, you would have to reproduce the entire table. Taconite gives you the flexibility to specify where content should be placed. In fact, this concept is straight out of the W3C DOM Load and Save specification.

Figure 1 shows the client HTML page. Note that there is only one link on the page (line 18). Clicking the link sends an AJAX request to the server, and the server's response is appended to the page.

Lines 7 and 8 reference Taconite JavaScript files. The taconite-client.js file is always required when Taconite is used. This file defines the AjaxRequest object, which is the heart of the Taconite client-side library. The taconite-parser.js file references the JavaScript-based Taconite parser. It is only required when you wish to perform the XHMTL-to-DOM parsing on the browser rather than on the server.

Lines 11-14 define the doHelloWorld function. Thanks to the Taconite framework, it's only two lines long. The first line creates an instance of the AjaxRequest object. The AjaxRequest object, as described by its name, encapsulates an AJAX request. Each instance of an AjaxRequest object creates its own instance of the XMLHttpRequest object, so you can create as many as you like without worrying about instances of XMLHttpRequest overwriting one another.

Line 18 defines the link that initiates the AJAX request when clicked. The link calls the doHelloWorld function, passing to it the URL of the AJAX service to be called.

The AjaxRequest object is created by passing a single argument to the object constructor. The argument is the URL to which the AJAX request will be sent.

The second line of the doHelloWorld function sends the request to the server. The AjaxRequest object defines a sendRequest method, which is called here to send the request. The rest is defined on the server, which we'll look at next.

Line 1 in Figure 2 is a directive indicating that the Content-Type of the page should be returned as text/xml. All Taconite responses must be returned with a Content-Type of text/xml, otherwise, the XMLHttpRequest object won't be able to parse it as an XML document. This file can be reproduced by any server-side technology; just set Content-Type to be text/xml.

Line 3 has the taconite-root XML tag, which is the root tag of all Taconite responses. All Taconite responses must have the taconite-root tag as the root tag. The presence of this tag ensures that the response is well-formed XML. Note that the taconite-root tag has an attribute of xml:space="preserve." This is to ensure that Internet Explorer handles whitespace correctly.

Line 5 opens the taconite-append-as-children tag. This tag says that the child elements of this tag will be appended as children to the context node. The context node is specified by the contextNodeID attribute. The value of this attribute must correspond to some element on the XHTML page. Remember the empty div element on Line 23 of the XHTML page, which had an ID attribute value of helloWorldContainer? This is where the message will be appended, because the contextNodeID attribute of the taconite-append-as-children tag has a value of helloWorldContainer.

The second attribute on the taconite-append-as-children tag is parseInBrowser, which has a value of true (when not using the JSP tags, parseInBrowser must always be true). This tells the AjaxRequest object that it needs to parse the response into JavaScript before running the JavaScript to produce the "Hello World" message.

Finally, the "Hello World!" message is defined on Lines 7-9. Notice how the message is simply defined as valid XHTML. In fact, the div tag even has an embedded style that makes the message font orange in color! This is the beauty of Taconite: you simply specify the new or updated content as regular ol' XHTML, and Taconite does the rest, without resorting to using the pesky innerHTML property.

Using Taconite with ColdFusion
AJAX really improves your user's experience. Your Web page appears to load faster because your application is responding to your user and only loading the necessary content. Entire page reloads are no longer necessary. How you approach designing your page changes. You become focused on how to respond to your user's actions. Your code becomes more precise and more manageable.

From the Team Behind AJAXWorld!
AJAXWorld Magazine is the pre-eminent independent vendor-neutral resource for the fastest growing new segment of the software business: entirely Web-based applications and experiences like Gmail, Google Maps, Live.com, MySpaces, and Flickr.

AJAXWorld Magazine recognizes that the next-generation user-centric Web is hurtling toward us and that it's a rich-media future in which AJAX, as the most talked about of all the Rich Internet technologies, is positioned firmly at center stage.

The first international AJAXWorld Conference & Expo which took place on October 2 - 4, 2006, at the Santa Clara Convention Center in Santa Clara, CA is sponsored by Adobe, Amazon, Apress, Backbase, ComponentArt, Cynergy Systems, Google, Helmi Technologies, IBM, ICEsoft, ILOG, Infragistics, JackBe, Laszlo Systems, Nexaweb, OASIS, Parasoft, Sun Microsystems, telerik, TIBCO, U7 Web Technologies, Visible Measures, Zapatec; including media sponsors AJAX Matters, AJAXWorld Magazine, BZ Media, ColdFusion Developer's Journal, DevtownStation.com, Eclipse Developer's Journal, Eclipse Review, Enterprise Open Source Magazine, Integration Developer News, ITtoolbox.com, Java Developer's Journal, LinuxWorld.com, Methods & Tools, Network World, Open Enterprise Trends, Sarbanes-Oxley Compliance Journal, SD Times, Software Test & Performance, SOA Web Services Journal, SYS-CON.TV, Web 2.0 Journal, and Web Developer's & Designer's Journal.

To date, more than 50 organizations have joined the OpenAjax Alliance, including:

Adobe
Ajaxian
American Greetings (AG/Interactive)
Backbase
BEA
Bling Software
Borland
Curl
Dojo Foundation
Eclipse Foundation
edge IPK
eLink Business Innovations
ENOVIA MatrixOne
Fair Isaac
Finetooth
The Front Side
Google
IBM
ICEsoft
Ikivo
ILOG
IN2
Innoopract
Intel
IT MILL
JackBe
Javeline
JWAX
Laszlo Systems
Merced Systems
Mozilla Corporation
Nexaweb
Nitobi
Novell
OpenLink Software
Openwave Systems
Opera
Oracle
Red Hat
SAP
Scalix
Seagull Software
Sitepen
Software AG
Sun Microsystems
Tibco
Vertex Logic
Vircom
Webtide
XML11
Zend Zimbra
Zoho

More Stories By Tom Schreck

Tom Schreck is a Macromedia certified ColdFusion MX 6.1 developer. He has been working with ColdFusion since 1997. Check out www.cfcPowerTools.com for more information on cfcPowerTools.

More Stories By Jason Doyle

Jason Doyle is a Web systems engineer at Thomson. He is currently focusing on Rich Internet Applications with the use of mash-ups in a service-oriented environment.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
BnkToTheFuture.com is the largest online investment platform for investing in FinTech, Bitcoin and Blockchain companies. We believe the future of finance looks very different from the past and we aim to invest and provide trading opportunities for qualifying investors that want to build a portfolio in the sector in compliance with international financial regulations.
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
Imagine if you will, a retail floor so densely packed with sensors that they can pick up the movements of insects scurrying across a store aisle. Or a component of a piece of factory equipment so well-instrumented that its digital twin provides resolution down to the micrometer.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settle...
Product connectivity goes hand and hand these days with increased use of personal data. New IoT devices are becoming more personalized than ever before. In his session at 22nd Cloud Expo | DXWorld Expo, Nicolas Fierro, CEO of MIMIR Blockchain Solutions, will discuss how in order to protect your data and privacy, IoT applications need to embrace Blockchain technology for a new level of product security never before seen - or needed.
Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
Nordstrom is transforming the way that they do business and the cloud is the key to enabling speed and hyper personalized customer experiences. In his session at 21st Cloud Expo, Ken Schow, VP of Engineering at Nordstrom, discussed some of the key learnings and common pitfalls of large enterprises moving to the cloud. This includes strategies around choosing a cloud provider(s), architecture, and lessons learned. In addition, he covered some of the best practices for structured team migration an...
No hype cycles or predictions of a gazillion things here. IoT is here. You get it. You know your business and have great ideas for a business transformation strategy. What comes next? Time to make it happen. In his session at @ThingsExpo, Jay Mason, an Associate Partner of Analytics, IoT & Cybersecurity at M&S Consulting, presented a step-by-step plan to develop your technology implementation strategy. He also discussed the evaluation of communication standards and IoT messaging protocols, data...
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
In his session at 21st Cloud Expo, Raju Shreewastava, founder of Big Data Trunk, provided a fun and simple way to introduce Machine Leaning to anyone and everyone. He solved a machine learning problem and demonstrated an easy way to be able to do machine learning without even coding. Raju Shreewastava is the founder of Big Data Trunk (www.BigDataTrunk.com), a Big Data Training and consulting firm with offices in the United States. He previously led the data warehouse/business intelligence and B...
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
When shopping for a new data processing platform for IoT solutions, many development teams want to be able to test-drive options before making a choice. Yet when evaluating an IoT solution, it’s simply not feasible to do so at scale with physical devices. Building a sensor simulator is the next best choice; however, generating a realistic simulation at very high TPS with ease of configurability is a formidable challenge. When dealing with multiple application or transport protocols, you would be...
Smart cities have the potential to change our lives at so many levels for citizens: less pollution, reduced parking obstacles, better health, education and more energy savings. Real-time data streaming and the Internet of Things (IoT) possess the power to turn this vision into a reality. However, most organizations today are building their data infrastructure to focus solely on addressing immediate business needs vs. a platform capable of quickly adapting emerging technologies to address future ...
We are given a desktop platform with Java 8 or Java 9 installed and seek to find a way to deploy high-performance Java applications that use Java 3D and/or Jogl without having to run an installer. We are subject to the constraint that the applications be signed and deployed so that they can be run in a trusted environment (i.e., outside of the sandbox). Further, we seek to do this in a way that does not depend on bundling a JRE with our applications, as this makes downloads and installations rat...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
In this strange new world where more and more power is drawn from business technology, companies are effectively straddling two paths on the road to innovation and transformation into digital enterprises. The first path is the heritage trail – with “legacy” technology forming the background. Here, extant technologies are transformed by core IT teams to provide more API-driven approaches. Legacy systems can restrict companies that are transitioning into digital enterprises. To truly become a lead...
Digital Transformation (DX) is not a "one-size-fits all" strategy. Each organization needs to develop its own unique, long-term DX plan. It must do so by realizing that we now live in a data-driven age, and that technologies such as Cloud Computing, Big Data, the IoT, Cognitive Computing, and Blockchain are only tools. In her general session at 21st Cloud Expo, Rebecca Wanta explained how the strategy must focus on DX and include a commitment from top management to create great IT jobs, monitor ...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
The IoT Will Grow: In what might be the most obvious prediction of the decade, the IoT will continue to expand next year, with more and more devices coming online every single day. What isn’t so obvious about this prediction: where that growth will occur. The retail, healthcare, and industrial/supply chain industries will likely see the greatest growth. Forrester Research has predicted the IoT will become “the backbone” of customer value as it continues to grow. It is no surprise that retail is ...