Ajax or Asynchronous Javascript and XML as it was first termed, is shorthand for Javascript UI development, particularly Javascript development that uses the XMLHttpRequest object. XMLHttpRequest and other techniques used to communicate to the server from Javascript prompted the invention of the word, using these techniques Web UIs driven by Javascript may be made more interactive with server data and more responsive, as small fragments of data may be exchanged efficiently between server and client.
Ajax driven applications differ from other rich UI technology driven applications such as Flash or Java by utilizing the other components of Web application development, namely HTML for document delivery and CSS for document styling, as well as sometimes even embedding other components such as Flash widgets.
A simple Ajax library that just implements a cross platform abstraction of XMLHttpRequest is the open source XHConn.
Ajax, in the sense of communication with the server without a complete reload of the page, dates back to 1996/7, with the inclusion of the IFrame feature in Netscape and IE3. Other early techniques include using image loading to communicate with the server from Javascript.
These early attempts eventually evolved into a formal IE4 feature created by Microsoft to be used in their Outlook Web Access project, which developed a rich UI that was similar to using the native Outlook by communicating with the server directly from Javascript and using other Javascript functionality extensively.
Years later, Google’s web mail project GMail used Ajax techniques to provide a similarly rich experience for email through a web browser. The public, free and cross browser application attracted the attention of web developers by highlighting what could be done with Javascript and Ajax techniques to provide an interactive application over the web.
In the glow of this renewed attention to Javascript and Ajax techniques, the Adaptive Path web consultant Jesse James Garrett coined the term “Ajax” to describe A New Approach to Web Applications
The article and the term caught on, becoming a catchword for rich Javascript driven web UI.
Ajax may have been initially defined as Asynchronous Javascript and XML, however Ajax techniques are commonly not XML, and sometimes not Asynchronous.
The formats used most frequently in Ajax applications for exchanging data between the client and the server are plain text, HTML, and JSON/Javascript variables. Plain text and HTML are quite commonly used as they are simple and small, and can be directly injected into the document quickly. JSON/Javascript variables are common for more in depth data manipulation by the client script, and are simple to parse, requiring only an eval evocation.
XML use is directly supported in the XMLHttpRequest object (as implied by the name), however due to the parsing costs, both in development time and client CPU time, it is rarely used.
While Ajax has enjoyed extreme popularity as a buzzword and catchphrase, and has been implemented to great effect in impressive applications beyond GMail, it has also attracted criticism, and applications using Ajax techniques have attracted criticism as well.
Ajax suffers from common complaints directed at Javascript driven applications. Some of these include problems with expected user behavior of the browser’s ‘back button’, accessibility problems from the perspective of users and search bots, and various cues generated by the browser such as the loading throbber that must be emulated directly by Ajax developers.
More on this topic can be found in the Ajax Mistakes article.
Another issue is cross browser coding, although Ajax techniques are available for virtually every web browser, support for various methods are almost never uniform, especially in the case of XMLHttpRequest, which has a few different implementations that must be coded for.
IE6 requires ActiveX be enabled for XMLHttpRequest to function, although IE7 will include it as a native object.
More on Ajax development issues can be found in Ajax-Development-Gotchas.
if any one can serve this with prototype and history keeper please help on that

At GigaOM’s recent Structure 08 event, Meebo co-founder and engineering chief, Sandy Jen, joined a panel to talk about scaling your computing infrastructure for explosive growth. Jen also spoke with Found|READ, this time to offer founders tips on how to overcome what she calls the internal scaling challenge: hiring.
Meebo launched in September 2005, when it unveiled the first Ajax application that allowed users to access several instant messaging clients (AIM, Jabber, Google Talk, etc.) from its home page. Back then, Jen and co-founders Seth Sternberg and Elaine Wherry were bootstrapping, even using personal credit cards to lease the three servers they needed in order to launch. With no money left over for marketing, they went guerrilla.
“Digg had started about six months earlier, so we said, ‘Let’s just Digg ourselves,’” Jen recalled. “We wrote a quick description of Meebo — ‘Web IM: AIM! Yahoo!; No downloads; draggable windows! It’s free!’— and went to bed. The next morning we had 600 Diggs, and our servers were overloaded.”
Three years later, Meebo has raised $37.5 million in venture capital, has all sorts of new products (and servers), gets 30 million unique visitors a month, and faces its toughest scaling challenge yet: “The No. 1 thing we worry about is hiring,” said Jen. To keep up with user demand, Meebo must grown to 50 employees from its current 30 by 2009 — a 67 percent increase.
In a fast-growing startup, maintaining your core values is crucial. “But how do you hire and keep your small team culture? It’s really hard,” Jen told us. “In the beginning it’s easy to ask your friends and people you trust for names. But eventually you’ll tap out your networks. Then where do you look for talent?”
In order to uncover new recruits — and not just the very talented people, but the right people — for her company, Jen has developed a few tricks:
1. Go to industry events. You want to hire people who are interested in the same things that you’re interested in. That means reaching out to people who attend the same events that you do. Once you’ve seen the same person at four of five events, make your move.
2. Keep track of smart comments in blogs and forums. Pay attention to the people who are commenting smartly on the stories you’re reading — especially if they’re doing so frequently. This is an indicator of their engagement and passion.
3. Look for people through your extra-curricular activities. You want people interested in your technology, but the right cultural fit means finding people who share your other values, too. A good indicator of shared values is a shared extra-curricular activity. Do you rock climb? Play ultimate Frisbee? (Jen does.) Common fun offers opportunities for bonding, which can be a great way to find new staff.
4. Go outside your geographic circle. There’s a lot of talent in the world. One of the first things Meebo did was commission its graphic design from a guy in Italy, whose work they found on an art web site. They hired him on a trial basis; today he’s Meebo’s Agent Icon.
5. Leverage contract arrangements. As Jen acknowledged, getting H-1B visas is a long process and a pain in the butt. But they’re worth it. If you find someone you want on your team, get them in the door, excited about your company and under contract as soon as possible. Meebo usually has six or seven people working under contract at any time.
6. Commit and be generous. Really talented people rarely advertise themselves, at least not as much as we’d like them to. You must court them. There is a lot of competition, so this could mean being flexible with hours or remote work options. And once you decide to hire someone, you have to welcome them with open arms.
7. Fire fast. When someone isn’t working out, have them leave quickly. In three years, two people have left Meebo — one left in three weeks, the other, in a few months. But a bad fit will contaminate your culture. You can’t afford that.
(Photo credit: Lea Suzuki, San Francisco Chronicle.)
For more on how Jen manages Meebo’s infrastructure, check out her interview with Om, below.


At GigaOM???s recent Structure 08 event, Meebo co-founder and engineering chief, Sandy Jen, joined a panel to talk about scaling your computing infrastructure for explosive growth. Jen also spoke with Found|READ, this time to offer founders tips on how to overcome what she calls the internal scaling challenge: hiring.
Meebo launched in September 2005, when it unveiled the first Ajax application that allowed users to access several instant messaging clients (AIM, Jabber, Google Talk, etc.) from its home page. Back then, Jen and co-founders Seth Sternberg and Elaine Wherry were bootstrapping, even using personal credit cards to lease the three servers they needed in order to launch. With no money left over for marketing, they went guerrilla.
???Digg had started about six months earlier, so we said, ???Let???s just Digg ourselves,’” Jen recalled. “We wrote a quick description of Meebo ??? ‘Web IM: AIM! Yahoo!; No downloads; draggable windows! It???s free!?????? and went to bed. The next morning we had 600 Diggs, and our servers were overloaded.???
Three years later, Meebo has raised $37.5 million in venture capital, has all sorts of new products (and servers), gets 30 million unique visitors a month, and faces its toughest scaling challenge yet: ???The No. 1 thing we worry about is hiring,??? said Jen. To keep up with user demand, Meebo must grown to 50 employees from its current 30 by 2009 ??? a 67 percent increase.
In a fast-growing startup, maintaining your core values is crucial. ???But how do you hire and keep your small team culture? It???s really hard,??? Jen told us. ???In the beginning it???s easy to ask your friends and people you trust for names. But eventually you???ll tap out your networks. Then where do you look for talent????
In order to uncover new recruits ??? and not just the very talented people, but the right people ??? for her company, Jen has developed a few tricks:
1. Go to industry events. You want to hire people who are interested in the same things that you’re interested in. That means reaching out to people who attend the same events that you do. Once you???ve seen the same person at four of five events, make your move.
2. Keep track of smart comments in blogs and forums. Pay attention to the people who are commenting smartly on the stories you’re reading — especially if they’re doing so frequently. This is an indicator of their engagement and passion.
3. Look for people through your extra-curricular activities. You want people interested in your technology, but the right cultural fit means finding people who share your other values, too. A good indicator of shared values is a shared extra-curricular activity. Do you rock climb? Play ultimate Frisbee? (Jen does.) Common fun offers opportunities for bonding, which can be a great way to find new staff.
4. Go outside your geographic circle. There’s a lot of talent in the world. One of the first things Meebo did was commission its graphic design from a guy in Italy, whose work they found on an art web site. They hired him on a trial basis; today he’s Meebo???s Agent Icon.
5. Leverage contract arrangements. As Jen acknowledged, getting H-1B visas is a long process and a pain in the butt. But they’re worth it. If you find someone you want on your team, get them in the door, excited about your company and under contract as soon as possible. Meebo usually has six or seven people working under contract at any time.
6. Commit and be generous. Really talented people rarely advertise themselves, at least not as much as we’d like them to. You must court them. There is a lot of competition, so this could mean being flexible with hours or remote work options. And once you decide to hire someone, you have to welcome them with open arms.
7. Fire fast. When someone isn???t working out, have them leave quickly. In three years, two people have left Meebo — one left in three weeks, the other, in a few months. But a bad fit will contaminate your culture. You can???t afford that.
(Photo credit: Lea Suzuki, San Francisco Chronicle.)
For more on how Jen manages Meebo’s infrastructure, check out her interview with Om, below.
