Develop Reference

Is it more efficient to let ajax get the html or get JSON and make the javascript create the html

The title says it all, but basically I use ajax to get information and I don't know if I should have PHP create the HTML which then gets returned to the client and then javascript just plugs it in or if I should have the server just send all the information through JSON and have javascript (jQuery) create all the html that holds it.
Which one is more efficient?
Thanks

I would say it is better practice to serve only the JSON data. Why?
Well, perhaps, you want to hook up a different type of client to your data service.
Maybe you create a mobile app, and it needs the same data, but wants to display it differently.
If you are providing the HTML markup as well, then now your mobile app has to parse the data it wants out of the HTML structure, rather than just dealing with the data right away.
On an efficiency scale, that depends on what you consider efficient.
For example, it would be efficient from a bandwidth perspective to only send the JSON. However, it would be more efficient from a processing standpoint on the target client to simply give it an HTML string to display.
If you are considering ever having different clients accessing the same data, though, then you want to create a single data interface that serves JSON (in your case), and allow the client to decide how to present that data.
Separation of concerns.

How can I convert an XML Object into a Javascript Object?

I have a project I need to do that requires the use of xml and javascript, however I'm not experienced in either.
Basicly its for a company that posts jobs in an rss feed using xml, and what they need is to have a page that allows a user to type in a search query, click a search button and have a list of available jobs returned back to them with only the title and the link, and upon clicking the link they will be directed to the full rss xml item. which they can then read.
Now as far as my logic goes, I don't know how to use jquery and quite honestly I don't think its necesary, I think that all this project needs is a bit of ajax however firstly one would need to create an xml object, convert it to a javascript object and only then manipulate it. etc...
If anyone has any insight I'd really appreciate it.

Parsing "Streaming" JSON

I have a grid in a browser.
I want to send rows of data to the grid via JSON, but the browser should continuously parse the JSON as it receives it and add rows to the grid as they are parsed. Put another way, the rows shouldn't be added to the grid all at once after the entire JSON object is received -- they should be added as they are received.
Is this possible? Particularly using jQuery, Jackson, and Spring 3 MVC?
Does this idea have a name? I only see bits of this idea sparsely documented online.

You can use Oboe.js which was built exactly for this use case.
Oboe.js is an open source Javascript library for loading JSON using streaming, combining the convenience of DOM with the speed and fluidity of SAX.
It can parse any JSON as a stream, is small enough to be a micro-library, doesn’t have dependencies, and doesn’t care which other libraries you need it to speak to.

You can't parse incomplete or invalid JSON using the browser's JSON.parse. If you are streaming text, it will invariably try and parse invalid JSON at some point which will cause it to fail. There exists streaming JSON parsers out there, you might be able to find something to suit your needs.
Easiest way in your case would remain to send complete JSON documents for each row.

Lazy.js is able to parse "streaming" JSON (demo).

Check out SignalR.
http://www.hanselman.com/blog/AsynchronousScalableWebApplicationsWithRealtimePersistentLongrunningConnectionsWithSignalR.aspx

March 2017 update:
Websockets allow you to mantain an open connection to the server that you can use to stream the data to the table. You could encode individual rows as JSON objects and send them, and each time one is received you can append it to the table. This is perhaps the optimal way to do it, but it requires using websockets which might not be fully supported by your technology stack. If websockets is not an option, then you can try requesting the data in the smallest chunks the server will allow, but this is costly since every request has an overhead and you would end up doing multiple requests to get the data.
AFAIK there is no way to start parsing an http request before it's finished, and there is no way to parse a JSON string partially. Also, getting the data is orders of magnitude slower than processing it so it's not really worth doing.
If you need to parse large amounts of data your best bet is to do the streaming approach.

How to do Javascript access a local database in txt format

I am newbie working on a 100% js prototype. It consist of 3 docs: an html page full of xml tags, a small dictionary in a text file format, and a js file with jquery.
The js needs to parse the xml tags (no problem here) and look into the mini-dictionary list for available translations.
Which is the best way to implement the mini-dictionary list. (No more than 50.000 records). Is there a way to load the list into a memory database and access it from js? Which is the usual path to take in this case? What is the simplest and machine-independent way to do this?
Any directions as to where should I research are greatly appreciated.

I would suggest encoding mini-dictionary with JSON data format, and then using AJAX to get that file and parse it. But then you are risking someone will just copy whole dictionary and steal your work.
That is, if you are not using server side language, like PHP. If you are using it, then just store everything into database and request just specific words with AJAX.

XML and Javascript: the right tool for the job?

For years I've been reading about XML and I have just not quite grokked it. Most documents I see about it simply explain the syntax (extraordinarily easy to understand) and say that it's portable: I've worked with Unix my whole life so the idea of putting things in plain text to be portable is hardly revolutionary. My specific question is that I have a document (my CV) that I would like to present to web visitors in several formats: as a webpage, as a pdf, or even as plain text. Is XML and Javascript the right approach to take?
What I need is for the document to be easily editable, conversion easy and just easy general upkeep. For example, when I publish a paper, I'd like to take less than five minutes to add the info and then have everything go automatically from there.
Give me your opinions: I also use LaTeX compulsively, so my current approach has been just to have my CV in LaTeX and to convert it to a web-page using LaTeXML. However, I sorta have the feeling that with everybody jumping up and down about XML and Javascript, that there might be something good to learn about it.
I would also like to simplify maintaining my homepage by not duplicating the same footer for every single page that I set up.
Thanks,
Joel
Edit: I'll also take any book recommendations!

I think this is a slight misunderstanding of the combination of JavaScript and XML.
XML, in and of itself is an excellent means of representing data. It's largely human-readable, and easily parsed with libraries in nearly every programming language. That is the main benefit of XML.
Using XML with JavaScript is certainly a solution, but I think it's a matter of the question you're asking. JavaScript can parse XML, and allow you to obtain and manipulate data from your XML document. If you want to grab data from a server without reloading your HTML page (synchronously or asynchronously), then using JavaScript and XML is a valid way to do that.
If you want to, however, display your XML as a webpage, you would likely be better off using XML and XSLT [wikipedia], or perhaps PHP and XPath, to transform the document into browser-readable HTML. On the other hand, you could use nearly any language to convert the XML to a plain-text file, rich text file, or store it in a normalized database.
To sum up, XML is a great way to store data, because it can be used in so many different ways, and by so many different languages. It's an answer to many different questions; you just have to figure out which questions you're asking.

To elaborate on my comment
The transformation to whatever output you desire is depending on how you store your CV on your server and whether you have the possibility to process it on the server. If you store it in XML, you can transform it to desired (binary) output using server based tools - that would for php be pdf and word (on windows server platform) for example. XML would be interesting from a mark-up point of view since it would make it clear where the table of contents, headers, lists of experience and so one would be found.
JavaScript cannot transform something into PDF or word, that has to be done on the server. What javascript can do is to get a text from the server in XML or JSON using AJAX and manipulate this into what the user sees on the screen. For XML that can be done with XSL(T) too. If you want for self-education purposes to use JavaScript, JSON is very nice since it is in my opinion more readable than XML and it creates a populated javascript object with the least work.
Footer in javascript: in the page have
<script type="text/javascript" src="footer.js"></script> and in footer.js, you can for example do
var footerText = 'Here goes whatever you want';
document.write(footerText);
Comparison between XML and JSON

I've got a webpage with browser-side XSLT transformation up and running for years. It's a playground, only some words in german. See how easy it is to build this on heese.net/test. You can switch between "Beispiel" (=Demo) and XSL. The sourcecode of the page in the iframe is the XML. You can do this serverside with 3 lines of PHP-code.
On Javascript: you can use it with XSLT and I show this on my site, but it can't interact. First the XSLT builds an HTML page out of your XML data and after this job is completely done the Javascript in the resultig HTML document begins to work.
Parsing XML with Javascript is a different task.