Welcome!

AJAX & REA Authors: RealWire News Distribution, Harald Zeitlhofer

Related Topics: AJAX & REA, .NET

AJAX & REA: Article

Google Maps! AJAX-Style Web Development Using ASP.NET

Taking asynchronous Web forms to the next level

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

I have three goals in this article. First, I want to provide a high-level overview of AJAX-style applications. My second goal is to provide a detailed description of asynchronous callback features of ASP.NET 2.0. Finally, I want to provide an insight into upcoming enhancements of tools and frameworks for building AJAX-style applications.

AJAX-style Web applications exhibit the following characteristics:

  • Asynchronous requests made to the Web server. The browser user interface is not blocked while waiting for a response from the Web server. The browser can continue to respond to user interaction while awaiting a server response.
  • High dependence on browser-based logic written in JavaScript. Recent enhancements to and standardization of the W3C DOM provide support for dynamic client-side updates to UI.
  • Exchange of nonpresentation XML-based data between the browser and the Web server. The XMLHttp object makes it possible to communicate with the Web server without the need to reload the page.
The big difference between an AJAX application and a traditional Web application is that every user interaction does not result in an HTTP request being sent to the Web server. Instead, browser-based logic implemented in JavaScript receives control that, in turn, decides whether to handle the request locally or to make an asynchronous call to the server. Upon the completion of the asynchronous call to the server, the client-side logic appropriately updates the relevant sections of the UI. This approach provides the following benefits:
  • The user experience is richer. For example, when a Google map user drags the map in one direction, an asynchronous request is made to the server in the background, to continue to fetch tiles beyond the edge of the screen. This way when the user drags the map further, the new image is readily available. This creates a perception of a speedier response.
  • Since the state is not lost across XMLHttp-based calls to the server, AJAX applications can avoid rerendering the UI widgets each time.
  • More logic residing in the browser reduces the number of roundtrips to the Web server, thereby improving the overall latency of the system.
For all the pros, AJAX-style applications have a number of cons associated with them as well. AJAX-style development is difficult because of the absence of framework (a collection of UI classes similar to the MFC toolkit for Windows) and IDE support (i.e., debugging, visual designers, etc.). One has to know at least two languages well (DHTML and JavaScript). Further, AJAX-style applications take longer to code because of the additional testing required to support multiple browser versions and types. Finally, as the JavaScript-based source is accessible to the end user, threat analysis becomes very important.

Fortunately, the arrival of things such as Atlas, AJAX.NET, and the Google Maps API etc. is a sign of better support for building AJAX-style applications in the future. In the next section, we will look into how the support for building AJAX applications is evolving over time and what to expect from the newly announced toolkits such as Atlas.

Let's start with the XMLHttp object, which was introduced by Microsoft and later implemented on other platforms including Mozilla and Apple's Safari browser. XMLHttp enables asynchronous requests to the Web server, which allows Javascript- based logic on the client to call the Web server without the need to reload the page.

In other words, it is possible to have interaction with the Web server in the background without causing a page reload - a side effect of the exchange between the browser and the Web server.

Using the XMLHttp object is straightforward. For the sake of simplicity, let's just consider IE specific syntax. The syntax for XMLHttp implementations on other browsers is similar.


request = new ActiveXObject("Microsoft.XMLHTTP");
if (request)
{
request.onreadystatechange = CallbackHandler;
request.open("GET", URL, true);
request.send();
}

function CallbackHandler()
{
if ((request.readyState == 4) && (request.status == 200)
{
string response = request.responseXML;

// Update the relevant sections of the UI

}
}
In the code snippet shown above, the first step is to instantiate the Microsoft.XMLHttp class. Next, we set the properties on the XMLHttp instance we just created, including the address of callback function that will get control when the XMLHttp request is complete. The callback function address is needed because we are making asynchronous calls to the server (an intent conveyed by setting the third parameter on the open method call to true). Inside the implementation for the callback function, we make additional checks to make sure that the request is complete.

More Stories By Vishwas Lele

Vishwas Lele is a principal architect at Applied Information Sciences (www.appliedis.com), a system and software engineering company specializing in .NET-based solutions. Vishwas also serves as the MSDN Regional Director for the Washington, DC area.

Comments (17) View Comments

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.


Most Recent Comments
Shabdar 03/25/08 11:57:26 AM EDT

If you are looking for Google Maps control for ASP.Net visit following link,

http://www.shabdar.org

This is a free open source control.

Steve 06/02/06 11:11:07 AM EDT

The title of the article is misleading. I see no mention of Google Maps in the content of the article in regards to ASP.NET.

I applaud the editors for coming up with such innovatively misleading bait to entice them to read the entire article, and all the embedded ads. Bravo!

AJAX News Desk 06/01/06 11:59:33 AM EDT

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

SYS-CON India News Desk 05/31/06 12:50:59 PM EDT

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

SYS-CON Italy News Desk 05/31/06 12:20:35 PM EDT

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

AJAX News Desk 05/31/06 11:49:13 AM EDT

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

not amused 02/23/06 03:57:06 AM EST

unreadable text thanks to floating add that is impossible to close

Sanjay Gupta 02/21/06 04:41:58 PM EST

Great explaination of the article.
I appreciate it!

Sanjay

SYS-CON Italy News Desk 02/19/06 05:53:45 PM EST

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

news 12/23/05 04:31:18 PM EST

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

SYS-CON UK News Desk 12/23/05 02:32:15 PM EST

Google Maps! Ajax-Style Web Development Using ASP.NET
In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

AJAX News Desk 12/23/05 11:41:04 AM EST

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

AJAX News Desk 12/23/05 10:42:12 AM EST

In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

Mike 11/14/05 02:21:56 PM EST

I am interested in Geo fencing...would any of the above technologies enable the development of a Google map which has geo fencing capabilities?

Thanks for any input,

Mike

News Desk 10/20/05 11:17:56 PM EDT

Google Maps! AJAX-Style Web Development Using ASP.NET. In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

.NET News Desk 09/08/05 12:58:07 PM EDT

AJAX-Style Web Development Using ASP.NET
In the past few months, the design pattern of combining Asynchronous JavaScript and XML (AJAX) to develop highly interactive Web applications has been growing in popularity. High-profile Web applications such as Google Maps and A9 are currently leveraging the combination of these technologies to produce rich client-side user experiences. The individual technologies that compose AJAX are not recent developments; they have been around for some time and have been continuously updated and improved. However, it is the recent confluence of these technologies that is leading to interesting possibilities.

Mark Petersen 09/07/05 10:22:23 AM EDT

The AJAX.NET URL is not correct.

I believe what you are looking for is:
http://ajax.schwarz-interactive.de/csharpsample/default.aspx

This library works in ASP.NET 1.1 as well.

Cloud Expo Latest Stories
Hardware will never be more valuable than on the day it hits your loading dock. Each day new servers are not deployed to production the business is losing money. While Moore’s Law is typically cited to explain the exponential density growth of chips, a critical consequence of this is rapid depreciation of servers. The hardware for clustered systems (e.g., Hadoop, OpenStack) tends to be significant capital expenses. In his session at 15th Cloud Expo, Mason Katz, CTO and co-founder of StackIQ, to discuss how infrastructure teams should be aware of the capitalization and depreciation model of these expenses to fully understand when and where automation is critical.
Over the last few years the healthcare ecosystem has revolved around innovations in Electronic Health Record (HER) based systems. This evolution has helped us achieve much desired interoperability. Now the focus is shifting to other equally important aspects – scalability and performance. While applying cloud computing environments to the EHR systems, a special consideration needs to be given to the cloud enablement of Veterans Health Information Systems and Technology Architecture (VistA), i.e., the largest single medical system in the United States.
In his session at 15th Cloud Expo, Mark Hinkle, Senior Director, Open Source Solutions at Citrix Systems Inc., will provide overview of the open source software that can be used to deploy and manage a cloud computing environment. He will include information on storage, networking(e.g., OpenDaylight) and compute virtualization (Xen, KVM, LXC) and the orchestration(Apache CloudStack, OpenStack) of the three to build their own cloud services. Speaker Bio: Mark Hinkle is the Senior Director, Open Source Solutions, at Citrix Systems Inc. He joined Citrix as a result of their July 2011 acquisition of Cloud.com where he was their Vice President of Community. He is currently responsible for Citrix open source efforts around the open source cloud computing platform, Apache CloudStack and the Xen Hypervisor. Previously he was the VP of Community at Zenoss Inc., a producer of the open source application, server, and network management software, where he grew the Zenoss Core project to over 10...
Most of today’s hardware manufacturers are building servers with at least one SATA Port, but not every systems engineer utilizes them. This is considered a loss in the game of maximizing potential storage space in a fixed unit. The SATADOM Series was created by Innodisk as a high-performance, small form factor boot drive with low power consumption to be plugged into the unused SATA port on your server board as an alternative to hard drive or USB boot-up. Built for 1U systems, this powerful device is smaller than a one dollar coin, and frees up otherwise dead space on your motherboard. To meet the requirements of tomorrow’s cloud hardware, Innodisk invested internal R&D resources to develop our SATA III series of products. The SATA III SATADOM boasts 500/180MBs R/W Speeds respectively, or double R/W Speed of SATA II products.
14th International Cloud Expo, held on June 10–12, 2014 at the Javits Center in New York City, featured three content-packed days with a rich array of sessions about the business and technical value of cloud computing, Internet of Things, Big Data, and DevOps led by exceptional speakers from every sector of the IT ecosystem. The Cloud Expo series is the fastest-growing Enterprise IT event in the past 10 years, devoted to every aspect of delivering massively scalable enterprise IT as a service.
As more applications and services move "to the cloud" (public or on-premise) cloud environments are increasingly adopting and building out traditional enterprise features. This in turn is enabling and encouraging cloud adoption from enterprise users. In many ways the definition is blurring as features like continuous operation, geo-distribution or on-demand capacity become the norm. NuoDB is involved in both building enterprise software and using enterprise cloud capabilities. In his session at 15th Cloud Expo, Seth Proctor, CTO at NuoDB, Inc., will discuss the experiences from building, deploying and using enterprise services and suggest some ways to approach moving enterprise applications into a cloud model.
Until recently, many organizations required specialized departments to perform mapping and geospatial analysis, and they used Esri on-premise solutions for that work. In his session at 15th Cloud Expo, Dave Peters, author of the Esri Press book Building a GIS, System Architecture Design Strategies for Managers, will discuss how Esri has successfully included the cloud as a fully integrated SaaS expansion of the ArcGIS mapping platform. Organizations that have incorporated Esri cloud-based applications and content within their business models are reaping huge benefits by directly leveraging cloud-based mapping and analysis capabilities within their existing enterprise investments. The ArcGIS mapping platform includes cloud-based content management and information resources to more widely, efficiently, and affordably deliver real-time actionable information and analysis capabilities to your organization.
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity. In his session at Internet of @ThingsExpo, Mac Devine, Distinguished Engineer at IBM, will discuss bringing these three elements together via Systems of Discover.
Cloud and Big Data present unique dilemmas: embracing the benefits of these new technologies while maintaining the security of your organization’s assets. When an outside party owns, controls and manages your infrastructure and computational resources, how can you be assured that sensitive data remains private and secure? How do you best protect data in mixed use cloud and big data infrastructure sets? Can you still satisfy the full range of reporting, compliance and regulatory requirements? In his session at 15th Cloud Expo, Derek Tumulak, Vice President of Product Management at Vormetric, will discuss how to address data security in cloud and Big Data environments so that your organization isn’t next week’s data breach headline.
The cloud is everywhere and growing, and with it SaaS has become an accepted means for software delivery. SaaS is more than just a technology, it is a thriving business model estimated to be worth around $53 billion dollars by 2015, according to IDC. The question is – how do you build and scale a profitable SaaS business model? In his session at 15th Cloud Expo, Jason Cumberland, Vice President, SaaS Solutions at Dimension Data, will give the audience an understanding of common mistakes businesses make when transitioning to SaaS; how to avoid them; and how to build a profitable and scalable SaaS business.
SYS-CON Events announced today that Gridstore™, the leader in software-defined storage (SDS) purpose-built for Windows Servers and Hyper-V, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Gridstore™ is the leader in software-defined storage purpose built for virtualization that is designed to accelerate applications in virtualized environments. Using its patented Server-Side Virtual Controller™ Technology (SVCT) to eliminate the I/O blender effect and accelerate applications Gridstore delivers vmOptimized™ Storage that self-optimizes to each application or VM across both virtual and physical environments. Leveraging a grid architecture, Gridstore delivers the first end-to-end storage QoS to ensure the most important App or VM performance is never compromised. The storage grid, that uses Gridstore’s performance optimized nodes or capacity optimized nodes, starts with as few a...
SYS-CON Events announced today that Solgenia, the global market leader in Cloud Collaboration and Cloud Infrastructure software solutions, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Solgenia is the global market leader in Cloud Collaboration and Cloud Infrastructure software solutions. Designed to “Bridge the Gap” between personal and professional social, mobile and cloud user experiences, our solutions help large and medium-sized organizations dramatically improve productivity, reduce collaboration costs, and increase the overall enterprise value by bringing collaboration and infrastructure solutions to the cloud.
Cloud computing started a technology revolution; now DevOps is driving that revolution forward. By enabling new approaches to service delivery, cloud and DevOps together are delivering even greater speed, agility, and efficiency. No wonder leading innovators are adopting DevOps and cloud together! In his session at DevOps Summit, Andi Mann, Vice President of Strategic Solutions at CA Technologies, will explore the synergies in these two approaches, with practical tips, techniques, research data, war stories, case studies, and recommendations.
Enterprises require the performance, agility and on-demand access of the public cloud, and the management, security and compatibility of the private cloud. The solution? In his session at 15th Cloud Expo, Simone Brunozzi, VP and Chief Technologist(global role) for VMware, will explore how to unlock the power of the hybrid cloud and the steps to get there. He'll discuss the challenges that conventional approaches to both public and private cloud computing, and outline the tough decisions that must be made to accelerate the journey to the hybrid cloud. As part of the transition, an Infrastructure-as-a-Service model will enable enterprise IT to build services beyond their data center while owning what gets moved, when to move it, and for how long. IT can then move forward on what matters most to the organization that it supports – availability, agility and efficiency.
Every healthy ecosystem is diverse. This is especially true in cloud ecosystems, where portability and interoperability are more important than old enterprise models of proprietary ownership. In his session at 15th Cloud Expo, Mark Baker, Server Product Manager at Canonical/Ubuntu, will discuss how single vendors used to take the lead in creating and delivering technology, but in a cloud economy, where users want tools of their preference, when and where they need them, it makes no sense.