I have a site that I want to load links in the centre column, so why would I use AJAX over an iframe?
AJAX is a system which allows you to get data - any data - from a server. This is in contrast to iframes which simply load in a HTML document or fragment based on a given URL.
THe strength of AJAX's flexibility over iframes is their ability to give you back raw data with which you then use to build or update your view. Consider this example: you have a dataset that needs to be displayed in tabular form, so you could set up a page that contains the table with your data in it and load that in via iframe.
A better option however, is to get the raw data from the server with AJAX and send it to your application uncluttered by markup and extra tags. Your page then builds the table in whatever part of the page it needs, according to how your application needs it to appear right at that point.
Where iframes can load HTML content that must be presented as it is built, AJAX allows the developer to separate the data from the way it is presented, giving them the freedom to manipulate it as much as they like and use it in as many ways, pages and applications as they need.
More Information
AJAX allows the client or web page to send data back to the server to do things with (such as changing passwords, updating settings, or transaction processing, etc.) so if your page or application needs two-way communication without refreshing the page, AJAX is probably the technology you'd use.
Also, using iframes restricts your ability to work with the data inside. An iframe creates a new context which you can think of as a container of sorts - the data inside is safe from the outside and vice versa. This often means your CSS won't flow down into your iframe giving you unexpected results. On some browsers, clicking a link in an iframe can actually cause the link's destination to load inside the iframe instead of changing the whole page - usually not what you want.
Related
Using the Open Graph protocol, an image can be signaled to applications such as Facebook to associate with a site link. For example:
<meta property="og:image" content="https://mysite.any/images/thumbnail.jpg">
However, this has a disadvantage: the image is a fixed one, i.e., it is always that same image whatever is the page. Obviously, using PHP, I can also select different existing images depending on the page being called, but doing this for any page on a site with hundreds of constantly updating pages is a mission impossible.
Ideally, I would like to be able to generate that image automatically when the server receives the HTTP call from the agent and generates the page content.
But how? Is there a simple way to do this, taking into account that the page is actually rendered by the browser and so the server actually has no idea how it will be represented? Probably I cannot do that by PHP but I need some JavaScript to do that. Is that correct?
I was reading up on ajax and how it empowers us to exchange data with a server behind the scenes and consequently avoid full page reloads. My confusion lies here, I don't really understand what full-page reloads mean. I think it's probably cause I've been working with ajax/react since the start I guess and have not really seen any webpage of mine fully reload when I access stuff from a database or an api.
It'd be great if someone could explain what they are and why did we need them before ajax?
A full page load is where the entire page is downloaded from the server. A page typically consists of several sections: header, footer, navigation, and content. In a classic web application without AJAX, a user clicks on a link to another page, and has to download the full page, even though only the main content is changing. The header, footer, and navigation all get downloaded again even though they don't change.
With AJAX there is the opportunity to only change the parts of the page that will change. When a user clicks on the link, JavaScript loads just the content for that link and inserts it into the current page. The header, footer, and navigation don't need to reload.
This introduces other problems that need attention.
When AJAX inserts new content into the page, the URL doesn't change. That makes it difficult for users to bookmark or link to specific content. Well written AJAX applications use history.pushState() to update the URL when loading content via AJAX.
There are then two paths to get to every piece of content. Users can either load the URL containing that content directly, or load the content into some other page by following a link. Web developers need to test and ensure both work.
Search engines have trouble crawling AJAX powered sites. For best compatibility, you need to employ server side rendering (SSR) or pre-rendering to serve initial content on a page load that doesn't require JavaScript.
Even for Googlebot (which executes JavaScript) care must be taken to make an AJAX powered site crawlable. Googlebot doesn't simulate user actions like clicking, scrolling, hovering, or moving the mouse.
Content needs to appear on page load without any user interaction
You must use <a href=...> links for navigation so that Googlebot can find other pages by scanning the document object model (DOM). For users, JavaScript can intercept clicks on those links and prevent a full page load by using return false from the onclick handler or event.preventDefault() in the click handler.
I'm taking an online course from a site that does not provide for asking questions about the content, so I am asking you.
This is one of the MUSTS for page titles:
"On a so-called single-page application — in which AJAX is used to bring in new content without refreshing or loading the entire web page — any time that the URL changes, the page title should be updated accordingly"
I always thought that if you used ajax to change part of a page the page itself would remain static. That is why would a URL change with an AJAX call. Are there any examples showing what this looks like?
AJAX requests don’t change the browser URL or history. To mimic the behaviour of traditional websites, single page apps will modify the URL and history and use the URL to change the view.
For more on changing the browser history, see Adding and modifying History entries.
This question exists in different flavors, but not for AJAX pages.
I use AJAX to pull a single video into my page and I want a custom FB share button for it. Everything I've read so far says that FB pulls the required title and image from meta-tags in the page's < head> section (og:image and og:title).
I've tried to change the meta properties when the AJAX call returns, before rendering the share button. This hasn't worked. It uses the values that were present upon initial page load. I have yet to encounter a single answer to this question.
Are there data attributes I can add to the 'fb-like' div to specify a custom title and image (similar to data-href)?
Danke!
You need an individual URL for each individual piece of content that you want to share. Open Graph objects (and simple shared links “become” such, automatically) are identified by their URL (og:url).
Now if your whole page is built on AJAX, you still need to create such individual URLs somehow – the Facebook scraper tool does not “speak” JavaScript, and relies solely on the OG meta information that the server delivers for any URL it requests.
Since the hash part of an URL is only of relevance client-side (and does not even get send to the server), “typical” AJAX URLs that rely on those to tell the client which piece of content to load in the background are no good here.
So if you want to share two pieces of content (videos) as http://www.example.com/?v=vid1 and http://www.example.com/?v=vid2, then you have to make sure that your server delivers the meta data for each video under its respective URL.
My website uses ajax.
I've got a user list page which list users in an ajax table (with paging and more information stuff...).
The url of this page is :
/user-list
User list is created by ajax. When the user click on one user, he is redirected to a page which url is : /member/memberName
So we can see here that ajax is used to generate content and not to manage navigation (with the # character).
I want to detect bot to index all pages.
So, in ajax I want to display an ajax table with paging and cool ajax effetcs (more info...) and when I detect a bot I want to display all users (without paging) with a link to the member page like this :
JohnBob...
Do you think I can be black listed with this technique ? If you think so, could you please provide an alternative solution by keeping these clean urls and without redeveloping the user-list (without ajax) ?
Google support a specification to make AJAX crawlable:
http://code.google.com/web/ajaxcrawling/docs/specification.html
I did an experiment and it works:
http://seo-website-designer.com/SEO-Ajax-Google-Solution
As this is a Google specification, you won't get penalised (unless you abuse it).
Saying that, only Google support it at the moment (AFAIK).
Also, I believe following the concept of Progressive Enhancement is a better approach. That is, create a working html website then make the JavaScript enhance it
Maybe use the urls with an onclick to trigger your AJAX scripting? Like
Some URL
I don't think Google would punish you for this, you primarily use JScript, but you do provide a fall back for their bot, so your site doesn't get any less accessible.
EDIT
Ok, I misunderstood. Then my guess would be you basically have two options:
1. Write a different part of your site where bots end up, or,
2. Rewrite your current site to for example always give a 'full' page, with an option to only get, say, the content div. Then you can get only the content with JavaScript, but bots will always get a nice page.