The business web application that I need to build for our company will use an accordion menu (such as the jQuery UI accordion).
I would like to use link jQuery click events to the accordion menu and load the content dynamically with the ajax .load shorthand.
Currently I'm dealing with an internal conversation where someone mentions that Ajax is slower than a regular browser request.
Now my question is: is that true, taken into account that:
The loading time of the accordion-content should be faster (all scripts / css / accordion / header loaded only once at the beginning);
The Ajax request does not influence the performance of any server actions;
Should I really use a browser request - and will it really be faster?
It seems very un-intuitive, using an accordion to use it as a static element that is just displayed on every page refresh.
I built a prototype before, using Ajax Load to load div containers with html and javascript, and it loaded as fast as a normal browser request would.
As for an answer, an ajax request is indeed smaller than a regular request for a page.
You have a few options where you could - pre-fetch the data, store this in an array or object and load it onclick of the slider,
or simply use ajax, this however will create another request which, if you have alot of users could potentially slow down your website.
pre-loading data into your html in hidden divs, or via a js.php directly into an array / object would be the most efficient way depending on the size of the contents.
Do know that ajax loaded content is not indexed by search engines and will be less SEO friendly.
Related
I am considering using ajax requests to pull content dynamically into a page and then binding that content up to the DOM using knockout.
Is there a way to load content dynamically into a page that makes the page look like it's content is being rendered by the server as normal get request?
If not, do most search engines read dynamic content today? For example, if one were to use an ajax call to fill in the title tag of a page - do most modern search engines support that crawl?
I'll admit that I'm pretty new web development (only been coding for about a year) and especially green when it comes to JS / jQuery.
A specific web page I've built loads different data based on hovering over certain categories: country clubs, resorts, hotels, etc. When I built the site on my local machine, the javascript function was super quick. However, on the live site, it has a long delay before the data swap happens.
The URL is: http://preferredparkingsolutions.com/client_list.html
Which links to a javascript function at: http://preferredparkingsolutions.com/scripts/clientHover.js
Which replaces the display div (#client_list) by pulling data from a text file.
Is there a better / faster way of doing this?
Yes, this could be optimised by loading the content in up-front and caching it. Currently you are doing a HTTP request each for each and every hover - even if the user has hovered over that element before, since the AJAX responses aren't being cached. Doing this would be your quickest win.
However, I can't see any case at all for having the content live externally. Is there any reason you're against having the content physically in the page and just using show/hide methods? There's various benefits to this - SEO, for one thing, since Google will find the content.
this is the external page you are loading http://preferredparkingsolutions.com/client_list.inc.html and the content looks little and looks like its a static page then why not just load every thing upfront and then just hide and show div's ? as Utkanos suggested you will aslo have a SEO benifit and also its HTTP request each for each and every hover. if you still want to load it externally lost load it once and cache it and use the cached version to hide and show divs.
My designer thought it was a good idea to create a transition between different pages. Essentially only the content part will reload (header and footer stay intact), and only the content div should have a transitional effect (fade or some sort). To create this sort of effect isn't really the problem, to make google (analytics) happy is...
Solutions I didn't like and why;
Load only the content div with ajax: google won't see any content, meaning the site will never be found, or only the parts which are retrieved by ajax, which arent't full pages at all
show the transitional effect, then after that 'redirect' the user to the designated page (capture the click event of a elements): effect is pretty much the same as just linking to another page, eg. user will still see a page being reloaded
I thought of one possible solution:
When a visitor clicks a link, capture the event, load the target with ajax, show the transitional effect in the meantime, then just rewrite the entire document with the content fetched with the ajax request.
At least this will work and has some advantages; the page reload will look seamless, no matter how slow your internet connection is, google won't really mind because the ajax content is a full html page itself, and can be crawled as is, even non-javascript browsers (mobile phones et al.) won't mind, they just reload the page.
My hesitation to implement this method is that i would reload an entire page using ajax. I'm wondering if this is what ajax is meant to do, if it would slow things down. Most of all, is there a better solution, eg. my first 'bad' solution but slightly different so google would like it (analytics too)?
Thanks for your thoughts on this!
Short answer: I would not recommend loading an entire page in this manner.
Long answer: Not recommended. whilst possible, this is not really the intent of XHR/Ajax. Essentially what you're doing is replicating the native behaviour of the browser. Some of the problems you'll encounter:
Support for the Back/Forward
button. You'll need a URI # scheme
to solve.
The Browser must parse
the entire page through AJAX.
This'll slow things down. E.g. if
you load a block of HTML into the
browser, then replace the DOM with
it, only then will any scripts, CSS
or images contained therein begin
downloading.
Memory - the
browser's not changing pages. Over
time (depending on the browser), I'd
expect the memory usage to increase.
Accessibility. Screen readers
will need to be notified whenever
the page content is updated. Might
not be a concern for you but worth
mentioning.
Caching. Browser
would not know which page to cache
(beyond the initial load).
Separation of concerns - your View
is essentially broken into
server-side pieces to render the
page's content along with the static
HTML for the page framework and
lastly the JS to combined the server
piece with the browser piece.
This'll make maintenance over time
problematic and complex.
Integration with other components -
you're already seeing problems with
Google Analytics. You may encounter
issues with other components related
to the timing of when the DOM is
constructed.
Whether it's worth it for the page transition effect is your call but I hope I've answered your question.
you can have AJAX and SEO: Google's proposal .
i think you can learn something from Gmail's design.
This may be a bit strange, but I have an idea for this.
Prepare your pages to load with an 'ifarme' GET parameter.
When there is 'iframe' load it with some javascript to trigger the parent show_iframe_content()
When there is no 'iframe' just load the page, with a hidden iframe element called 'preloader'
Your goal is to make sure every of your links are opened in the 'preloader' with an additional 'iframe' get parameter, and when the loading of the iframe finishes, and it calls the show_iframe_content() you copy the content to your parent page.
Like this: Link clicked -> transition to loading phase -> iframe loaded -> show_iframe_content() called -> iframe content copied back to parent -> transition back to normal phase
The whole thing is good since, if a crawler visit ary of your pages, it will do it without the 'iframe' get parameter, so it can go through all your pages like normal, but when you use it in a browser, you make your links do the magic above.
This is just a sketch of it, but I'm sure it can be made right.
EDIT: Actually you can do it with simple ajax, without iframe, the thing is you have to modify the page after it has been loaded in the browser, to load the linked content with ajax. Also crawlers should see the links.
Example script:
$.fn.initLinks = function() {
$("a",this).click(function() {
var url = $(this).attr("href");
// transition to loading phase ...
// Ajax post parameter tells the site lo load only the content without header/footer
$.post(href,"ajax=1",function(data) {
$("#content").html(data).initLinks();
// transition to normal phase ...
});
return false;
});
};
$(function() {
$("body").initLinks();
});
Google analytics can track javascript events as if they are pageviews- check here for implementation:
http://www.google.com/support/googleanalytics/bin/answer.py?hl=en-GB&answer=55521
I like that, these days, we have an option for how we get our web content from the server: we can make an old-style HTTP request (with its own URL in the browser) or we can make an AJAX call and replace parts of the DOM on the fly.
My question is this: how do you decide which method to use when there's an option to use either?
In the "old days" we'd have to redraw the entire page (including the parts that didn't change) if we wanted to show updated content. Now that AJAX has matured we don't need to do that any more; we could, conceivably, render a "page" once and just update the changing parts as needed. But what would be the consequences of doing so? Is there a good rule of thumb for doing a full-page reload vs a partial-page reload via AJAX?
If you want people to be able to bookmark individual pages, use HTTP requests.
If you are changing context, use HTTP requests.
If you are dividing functionality between different pages for better maintainability, use HTTP requests.
If you want to maximize your page views, use HTTP requests.
Lots of good reasons to still use HTTP requests - Stack overflow is a wonderful example of those divisions between AJAX and HTTP requests. Figure out why each function is HTTP or AJAX and I'm sure you will derive lots more reasons when to use each.
My simple rule:
Do everything ajax, especially if this is an application not just pages of content. Unless people are likely to want to link to direct content, like in a blog. Then it is easier to do regular full pages.
Of course there are many blended combinations, it doesn't have to be one or the other completely.
A fair amount of development overhead goes into partial-page reloads with AJAX. You need to create additional javascript handlers for all returned data. If you were to return full HTML blocks, you would still need to specify where the content should go and whether or not it's replacing other content. You would potentially have to re-render header tags to reflect content changes and you would have to implement a history solution to make sure search engines can index each page (using SWFAddress jQuery plugin, for example). If you return JSON encoded data you have an additional processing step.
The trade-off for reduced bandwidth usage by not using a page refresh is offset by an increase in JS code and event bindings which could affect page rendering speed as well as visual effects.
It all really depends on your target audience and the overall feel you are trying to go for on your page. AJAX and preloaders are flashy, and people love flashy things. If you believe the end-user experience will improve by adding partial page loads by all means implement them.
I am new to ajax and i wanted to know if we can load a complete new page and not just a part of it using ajax. Please give a small example script for understanding if this is possible. Here i am trying to display only one url to user while i change from one page to another when he clicks on any of the links in the page.
You can of course request for a new page and load it via body.innerHTML = ajax.responseText;
I would strongly recommend against this though for reasons outlined in this post: Why not just using ajax for Page Requests to load the page content?
The whole premise really is that with
AJAX you don't need to reload the
whole page to update a small
percentage of that webpage. This saves
bandwidth and is usually much quicker
than reloading the whole page.
But if you are using AJAX to load the
whole page this is in fact
counterproductive. You have to write
customised routines to deal with the
callback of the AJAX data. Its a whole
lot of extra work for little to no
increase in performance.
General rule for where to use AJAX: If
your updating >50% of your page, just
reload, else use AJAX.
You will not only need to request for the new page, but then also take care of ensuring the old styles on the current page are removed and don't interfere with the new page. Theres all sorts of problems associated with what your trying to do. It's possible, but I recommend not to do it.
edit: actually you might be able to just do document.write(ajax.responseText) which should take care of overwriting everything in the document, including css styles etc. Though still don't recommend it.
When you're finished with processing the AJAX request simply use this JS line:
window.location.replace('<URL of the new page>');
This has exactly the effect of loading the new page via
....
When you make an AJAX request, a request goes off and brings you the contents of the URL that you have requested. Now technically you can do whatever you like with the contents (which could be HTML), you can replace any element within the DOM with it. Be careful however of replacing EVERYTHING on the page, you are more likely just going to want to replace what is within the tags.
If what you want to do is show one URL for multiple pages, AJAX is overkill. Why not just use an IFRAME?
This could be useful if your page was unsure if it was expecting back errors to be inserted onto the page or a "new" submission confirmation page. This can be used when you want to put a validation servlet (or whatever) in front of the submission servlet (or whatever). If the page always hits the validation servlet, you hide the submission servlet which actually performs the data update. In the case where the validation passes, forward to the submission servlet. The user never knows what happened in the background.
When the page gets a response back you could just look at the first portion of the response text and determine if it had a keyword set by the server, which means this is a new page. Remove the keyword from the text, and do document.write(ajax.responseText); as described previously. Otherwise insert the response text into your errorBox div and let the user retry submission.