I need to create a portable script to give to others to implement on their websites that will dynamically show content from my database (MySQL).
I know AJAX has a cross-site problem, but it seems that Google's ad's somehow manage the effect in a cross-browser / cross-site fashion.
Knowing that I have to give people a simple cut/paste snippet to put in their website...how can I achieve this? How did Google?
They use an <iframe>, so the ad is served from their server, and can talk to their database. I'm not actually sure that they use any sort of AJAX from their ads, though; they appear to just be mostly static content, with a few scripts for tweaking the formatting (which are optional, since they want their ads to be visible even if users have JS turned off).
Remember, you can always look into this on your own, and see what they did. On Firefox, use Firebug to explore the html, css, and scripts on a site. On WebKit based browsers (Safari, Chrome, and others), you can use the Web Inspector.
Google's ad code is loaded via a script tag that calls a remote javascript file. The AJAX restrictions that are generally enforced with xmlhttp, iframe, and similar AJAX requests don't apply when it comes to loading remote javascript files.
Once you've loaded the javascript file, you can create iframes in your page that link back to the actual hosted content on your server (and feed them any data about the current page that you wish).
jQuery has built in support for jsonp in their ajax calls. You may want to lookin in to using that if you are really needing to use ajax.
http://api.jquery.com/
http://docs.jquery.com/Ajax
You don't need iFrames and you don't need AJAX. It's really, really simple!
You pull in a remote JS file that is actually a constructed file from php/asp/whatever. In your JS file you have a document.write script that writes the content. It's that simple.
We do this all the time with media stored on separate sites. Here's an example.
YOUR SERVER: file.php (which outputs js)
<script>
document.write("I'm on a remote server");
</script>
OTHER SITE:
<script src='http://www.yourserver.com/file.php'></script>
And it will output the content generated by the script. To make the content customized you can put in script vars above the script call that will adjust what your file pulls out. From there it's pretty straightforward.
I realize this question is a year old, but I've written a library that can help with the document.write part of the problem (whether this is a TOS violation, I don't know) writeCapture.js. It's pretty simple:
$('#ads').writeCapture().html('<script src="whatever-your-adsense-code-is"> </script>');
The example uses jQuery, but you can use it standalone as well.
Related
I have a project where we're using an iframe. However, project specs have changed and we can no longer use the iframe. Instead we need to request the html page in the background and display it on page when loaded.
Any ideas on how to do this via Ruby (rails). Thought best to ask for general direction before diving in.
Thanks!
load it with ajax, and do a body append
It depends on where you want to have the work occur, on the back-end in your Rails code, or in the user's browser via JavaScript, as #stunaz suggests.
Keeping it in the browser and loading via JavaScript will expose the HTML page's location to the user, which might not be desirable. Loading it from the back-end and including it in the HTML emitted to the browser will hide the source entirely.
If you want to do it on the back-end, the simplest thing is to either load the file from the local drive, if it is local using File.read. If it's on a different machine, you can use Open::URI to pull it in. Either way, you'd then insert it into the HTML in the right spot. How you do that depends on what you are using to generate the outgoing HTML.
I have a page on my site which has a list of things which gets updated frequently. This list is created by calling the server via jsonp, getting json back and transforming it into html. Fast and slick.
Unfortunately, Google isn't able to index it. After reading up on how to get this done according to Google's AJAX crawling guide, I am bit confused and need some clarification and confirmation:
The ajax pages need to be implement the rules only, right?
I currently have a rest url like
[site]/base/junkets/browse.aspx?page=1&rows=18&sidx=ScoreAll&sord=desc&callback=jsonp1295964163067
this would need to become something like:
[site]/base/junkets/browse.aspx#page=1&rows=18&sidx=ScoreAll&sord=desc&callback=jsonp1295964163067
And when google calls it like this
[site]/base/junkets/browse.aspx#!page=1&rows=18&sidx=ScoreAll&sord=desc&callback=jsonp1295964163067
I would have to deliver the html snapshot.
Why replace the ? with # ?
Creating html snapshots seems very cumbersome. Would it suffice to just serve simple links? In my case I would be happy if google would only index the things pages.
It looks like you've misunderstood the AJAX crawling guide. The #! notation is to be used on links to the page your AJAX application lives within, not on the URL of the service your appliction makes calls to. For example, if I access your app by going to example.com/app/, then you'd make page crawlable by instead linking to example.com/app/#!page=1.
Now when Googlebot sees that URL in a link, instead of going to example.com/app/#!page=1 – which means issuing a request for example.com/app/ (recall that the hash is never sent to the server) – it will request example.com/app/?_escaped_fragment_=page=1. If _escaped_fragment_ is present in a request, you know to return the static HTML version of your content.
Why is all of this necessary? Googlebot does not execute script (nor does it know how to index your JSON objects), so it has no way of knowing what ends up in front of your users after your scripts run and content is loaded. So, your server has to do the heavy lifting of producing a HTML version of what your users ultimately see in the AJAXy version.
So what are your next steps?
First, either change the links pointing to your application to include #!page=1 (or whatever), or add <meta name="fragment" content="!"> to your app's HTML. (See item 3 of the AJAX crawling guide.)
When the user changes pages (if this is applicable), you should also update the hash to reflect the current page. You could simply set location.hash='#!page=n';, but I'd recommend using the excellent jQuery BBQ plugin to help you manage the page's hash. (This way, you can listen to changes to the hash if the user manually changes it in the address bar.) Caveat: the currently released version of BBQ (1.2.1) does not support AJAX crawlable URLs, but the most recent version in the Git master (1.3pre) does, so you'll need to grab it here. Then, just set the AJAX crawlable option:
$.param.fragment.ajaxCrawlable(true);
Second, you'll have to add some server-side logic to example.com/app/ to detect the presence of _escaped_fragment_ in the query string, and return a static HTML version of the page if it's there. This is where Google's guidance on creating HTML snapshots might be helpful. It sounds like you might want to pursue option 3. You could also modify your service to output HTML in addition to JSON.
I've more or less given up on this. There really seems no alternative to generating the html on the server and delivering it in the html bdoy if you want goolge to index your directory.
I even tried adding a section wraped a .net user control which implemented a simple html version of the directory. But google also managed to ignore ..
So in the end my directory has been de-ajaxified. :(
I have no idea about AJAX programming features. I just know that it is Asynchronous Javascript and XML.
Please help me in knowing about this language.
I have gone through many AJAX tutorials. But none of the programs are running. Why I don't know.
Do we save the file with .HTML extension?
Read:
AJAX Tutorial by W3Schools.
AJAX Programming by Google Code University
To start coding you can get the Ajax Control Toolkit by Microsoft. You should read Ajax Control Toolkit Tutorials to get a grasp of it.
You can use the free Microsoft Visual Web Developer 2010 Express Edition as your IDE.
Aside from the correct responses that the others gave you, judging from your question I think you first need to learn about client-side and server-side code.
Do we save the file with .HTML extension?
Yes and no. You will have an HTML frontend, that for instance contains a button. This will be interpreted from the client's (=user) browser. In fact it may be rendered differently depending on the browser/OS/etc.
Now, you attach some Javascript code to this button. This also runs on the client's browser, and creates a XMLHttpRequest object, either directly or through the use of a library (JQuery & Co.). Note that a library is not necessary to do an AJAX request. It will make your life easier if you do a lot of AJAX calls, but it is not essential.
And here's where the magic happens: the XMLHttpRequest object will call asynchronously (i.e.: without reloading the page) a server-side page. This may be a PHP, ASP, Perl etc etc file that does something on the server, for instance queries a database. This part of the operation is absolutely independent from the client. The user can close the browser before the server-side code finishes to load and the server will not know about it.
Once the server-side code has finished executing it returns to the client with some response data (e.g. a piece of XML, JSON, HTML or whatever you like). Finally the client executes (or not) some other Javascript code in response to this, for example to write on the screen, again with no reloading of the page, something based on what the server has returned.
Maybe I can help you understand AJAX by clarifying the concepts a bit.
Please help me in knowing about this language.
AJAX is not a language, it is a way of using existing techniques to improve the user experience of a web site. The language is Javascript in the browser but you can use any server side technique that you feel comfortable with (ASP.NET, Java, PHP, Ruby etc.)
Do we save the file with .HTML extension?
Well, that is not really the point. What you have to grasp here is that there is a server and a browser that interact with each other. Yes, you can use static HTML files for your pages (and save them as .html files), but you'll need a server to respond to the requests of the browser. This may be why your sample code is not working; you need to set up a server that works with your pages.
The whole idea behind AJAX is to improve the user experience by not reloading the entire page when a user interacts with it. You request the data you need and update the page by using Javascript to update the HTML. This is called an out-of-band or asynchronous request.
I just know that it is Asynchronous Javascript and XML.
That is what the acronym stands for but it doesn't quite cover what the technique is for, nor is it accurate any more. In the beginning XML was used to transfer data from the server to the client. People found that XML is not really that easy to work with in Javascript so now it's more common to use JSON. JSON is a snippet of javascript that can be evaluated in the browser. The snippet creates javascript object(s) that represent the data.
If you use a Javascript library, like others have suggested here, you won't have to worry about many of the details though.
Before you get into AJAX you should make sure that you understand:
HTML and CSS
Javascript
how to modify HTML with Javascript
how a browser requests information from a server
how to handle requests on the server
If you are not comfortable with all of these concepts, stick with 'regular' web pages and try to improve your knowledge step by step.
Once you get the basic knowledge from W3school, I suggest you use a framework. Usually developers do not use XMLHttpRequest at all. Instead, javascript frameworks like ExtJS, jQuery and other frameworks make your work simple. I suggest you learn bit of javascript as well. check out jQuery.
Just to add that AJAX is rarely used in its pure form with XMLHttpRequest. You will often use it as a part of AJAX UI libraries which make your life easier. If you are from the Java world - such an AJAX library is Richfaces.
Instead of worrying about how to do AJAX, use something that allows you to forget about it. Frameworks like NOLOH do AJAX (and Comet) for you automatically without you having to do a thing. Just concentrate on your application, and business logic and it does the rest.
Really, everything is done via AJAX if available, automatically. No work on your part. If you're don't want to spend much time researching it, check out this short video that was demonstrated at Confoo PHP Conference this past March http://www.youtube.com/phpframework#p/u/11/cdD9hSuq7aw.
For all those worried about, well, if it's all AJAX, what about search engines? No need to worry, http://dev.noloh.com/#/articles/Search-Engine-Friendly/.
So instead of having to worry about all these different technologies, or the client-server relationship, you can sit down, code and have your website/WebApp working in no time.
You can read about NOLOH is this month's cover story of php|architect magazine, http://www.phparch.com/magazine/2010/may/.
Enjoy.
Disclaimer: I'm a co-founder of NOLOH.
It is easy one. Ajax getting data from server side by client side execution. We have to do use XMLHttpRequest to get the result.
I am loading content from another page and depending on the content of page, changing content of my page and this is giving me cross site scripting issues.
When i use iframe, since the content is from other domain, content of iframe becomes inaccessible.
When i use ajax and try to inject the content as plain html code, XmlHttpRequest object throws permission denied exception due to cross site scripting.
When i use JSONP, such as getJSON in JQuery, it only supports GET protocol and it is not adequate for further processing.
I wonder what other options i can try. Heard that DOJO, GWT,Adobe Air do some XSS, but dont know which one is the best.
Thanks,
Ebe.
Without JSON-P, your only option is to run a proxy script on your own server that fetches the content from the external site and pipes it back to the browser.
The browser fetches the content from the script on your server, hence no cross-domain issues, but the script on your server dynamically fetches it from the external site.
There's an example of such a script in PHP here: http://www.daniweb.com/code/snippet494.html (NB. I haven't personally used it).
If you have control over both domains, take a look at EasyXDM. It's a library which wraps cross-browser quirks and provides an easy-to-use API for communicating in client script between different domains using the best available mechanism for that browser (e.g. postMessage if available, other mechanisms if not).
Caveat: you need to have control over both domains in order to make it work (where "control" means you can place static files on both of them). But you don't need any server-side code changes.
To add to what RichieHindle says, there are some good script (Python+Cron) that you can plonk on your server and it will check for changes to a POST/GET location and cache the changes on your server.
Either set your triggers low (once every 10 mins/ 1 per day) or you might get blacklisted from the target.
This way, a local cache won't incur the HTTP overhead on every AJAX call from the client.
Right now i'm building a firefox plugin that duplicates some functionality on my website. It takes in an email address and then returns information to the user. The easiest way to do this in the plugin is to use an Iframe and render that super simple form on my website. All of this works great, but to make the plugin really useful, i would like the plugin to have access to the information that the iframe renders, so it can use it in the current window that the user is in.
Is it possible to pass information back through an Iframe in this manner? I know there are quite a few domain access restrictions with Iframes, so any help or insight is appreciated!!
I've done this two ways.
If the iframe is on the same domain as the parent website, you can just, in javascript, access window.parent.
If it isn't, however...I've done a dirty trick. I'll share it here, though, as it may help.
We created a page on the other domain, which would call to window.parent.parent. We put that in a hidden iframe inside the iframed page, and send it a querystring argument or two. It's not pretty, but it gets around cross-domain scripting problems.
This basically means that you have this sort of thing:
admin.example.com
content.example.com - iframe
admin.example.com?contentid=350 - hidden iframe that makes a window.parent.parent call.
Is the point of this whole exercise functional testing of your website? If so, instead of your custom Firefox plugin, consider using Selenium to automate interactions with websites. It works with all major browsers and supports the inspection of page elements you are trying to do (using XPath). It also features a Firefox plugin called Selenium IDE that allows you to conveniently "record" your interactions with a website for automated playback later.