I understand that frames are a lot more typing work to implement than Iframes, and that they require a lot more styling than Iframes. I am currently working on a website which must download some content (in fact, an entire set of webpages) from another website, one - by - one of course depending on the user's action on the main website. Iframes seem to be a short and rowdy way to implement this requirement, but what I am worried about is performance and integrity.
I would like some advice on what I would rather use when the following criteria is met:
The pages that must be downloaded onto my webpage are quite large (width and height)
Contains multiple images
Experiences occasional downtimes (maintainence)
any ideas for a man in wonder?
At this point, go with iFrames:
iFrame is HTML5. Frameset is obsolete in HTML5.
You have to load pages into each Frameset. iFrames can be embedded anywhere in a document.
You can style, hide, resize either, but iFrames are much easier to work with in this regard.
I've seen cases where the developer went with Frameset because he couldn't get the iFrame to size properly, but this isn't too big a deal with a little Javascript (if even that). The only reason to use a Frameset is if you don't fear it's eventual deprecation with modern browsers, and/or if you can't get iFrames to size the way you want based on the content you're integrating and need a quick solution.
If this is about display of 3rd party data in your site, you could use data feeds from the other sites if they're available, or use a screen scraper to extract the information you need, then display it in your own way on the page.
Unless it needs to look exactly like to other page.
Check out this link on screen scraping for ASP.NET
Related
Frames/ Framesets has been deprecated.
Iframes are not recomended for various reasons.
Ajax is not always an option since one of the providers may not support it.
So how does one converge & display multiple html content from two different sources in a Asp.Net 4.0 or higher page as per modern HTML standard ?
Should i focus completely on ajax/partial page related development or continue using Iframe as a stop gap measure hoping they dont deprecate it too in the near future ?
well there was a time when even facebook was on iframe, now its all about partial responses. But iframes are not going anywhere soon ,we still get many of our client requirement specific to iframes and if it suits your need to achieve compatibility why are you confusing yourself with alternates.
besides that html5 has added some new spices to iframe so its clear that this thing is not going in bin.
so in the end , i would suggest:
1. Go for ajax/partial/jquery if you want your application to be both interactive & user friendly.
2. If compatibility is a big issue then go straight to iframes.
Regards
I am about to develop a web site for data entry. It will have hundreds of data entry pages. Previously i have made extensive use of iFrames from the menuing system.
Is this now best practice, i number of developers i have mentioned this to have questioned the use of iFrames saying there are better techniques now. However no one could give me a reason not to use the iFrame.
Does anyone have some opinions on the use of iFrames and the reason i should not use them? If not an iFrame then what?
An iFrame is to embed foreign content, another site or another page of your site. Web is not only about what you see but about semantic meanings.
Using iFrames is the most effective way to kill your ranking in search engines and also to difficult web browsing since a browser cannot tell what part of the content represents what or how they are related to each other.
For instance, navigate into an iFrame based page and bookmark an internal page, then come back through the bookmark and see the results.
Do a search in Internet and there are many more explanations about this.
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For me iframes are pure evil (well, maybe not so pure). They seems to make a lot of troubles. Yes, your whole site will load once and then you can just load single pages. But people invented AJAX for this purpose.
One of the biggest issues I found with iframe was that I couldn't paste a link to one of the subpages, because the URL never changed (yes, I know there is a workaround for this). Second thing, web search engines may have problems indexing such pages.
Sometimes the accessibility of this sites are worse and some browser can even display them improperly.
There are better ways to design layouts without iframes. Everyday I can see some one asking at SO questions, like "How to access iframe with jQuery?".
So what are the benefits of iframes? What reason can it be to still use them? I just would like to know why.
I can think of 2 reasons (at the moment) why people would still use iframes instead of AJAX:
1) Iframes circumvent the cross domain origin policy (images, scripts, and styles do not). This can be useful for pulling in sites / content from other domain names relatively safely. Basically, this allows the advantage of being able to visually show data from other domains without letting them stomp all over your page with unlimited access (like something like JSONP would be able to do).
2) You can load multiple types of resources from within an iframe, not just certain mime-types (you're relatively limited to application/javascript, application/x-javascript, text/css, text/xml, image/png, image/jpeg, image/gif with scripts, XHR, images, and sources). For instance, if I want to show you a PDF, I can open an iframe and let the Adobe Reader plugin show you that file. Additionally, in the same domain, if I want to pipeline a script, style, and image all together (inline on the page, image would have to be data URI), I can accomplish this with an iframe (and if it's in the same domain, port, and protocol I can access it with JavaScript as well).
Did you know that Gmail is a set of iframes? The visible part is just clever positioning. Additionally, many OAuth implementation (Twitter, Facebook, Google, Yahoo!) usually use iframes to associate a user on their domain with a successful authentication URL (for after the user logs in).
IFRAMEs are used to embed and isolate third-party content into a website.
Most of web advertising solutions are based on iframes - because they give security (cross-domain policy) and isolated rectangle on screen which can be fully managed by third party content and scripting (a common use case is advertisments).
Another modern use of IFRAMES is a management of history (common back button workaround) of AJAX applications.
FRAMEs are poor version of IFRAMES. Their use is declining.
If a user has javascript disabled, iframes will work when ajax doesn't. This is not out of the question, considering that people use things like NoScript.
I use them on ajax websites, when I need to upload files without reloading the page.
I still see iframes being used in large corporations where they provide a single sign on which injects header information about the authenticated user which is then passed, via an iframe, towards the actual application(s). Since the "portal" surrounding the iframe handles all the specific authentication details those applications behind it don't need to have each an implementation for it, making things easier to make for the development team and having a single place to monitor and adjust authentication details of users.
There are plenty of technical reasons to use them (especially the security issue mentioned by Dan Beam).
What you shouldn't do is use iframes “like frames”, doing navigation to new pages by updating the iframe only. As you say, this prevents the navigation from being bookmarkable/linkable, responding to the normal navigation buttons, and providing useful link affordances like open-in-new-tab.
But that's not peculiar to iframes. You can see more and more pages where the navigation is done by fetching new content with XMLHttpRequest and writing it to the main content div's innerHTML. Often this is done with jQuery load() and clever-clever slidey animations. This breaks navigation just as badly as iframe-used-as-frame, or indeed old-school framesets. It's a shame so many web authors are using this tactic believing it to be a super-modern web design methodology, when really it's just a new skin on yesterday's despised framesets.
You can work around it in both cases, but it means you have to store a viewstate in the # fragment identifier part and support proper hash-navigation, which isn't trivial. Even then you've still got problems with non-JS agents like search engines; you end up having to have a parallel ?-based and #-based navigation to support both. It's a pain and most don't bother.
Framesets are outdated as of HTML 5, and sometimes you need to have a frame with another site within a site.
Also AJAX can only do so much. Try uploading a file to a site on another domain through https without an iframe. AJAX won't help you there.
In addition to others reasons, I have one specific usage of iframe in my application. Unfortunately, the target browser in my case is Internet Explorer 6. I need to have a footer and a header that are fixed in my web pages. The main part of this page is scrollable.
However, there is a bug in IE6 where I cannot display a div element on top of select elements using the z-index CSS property. Thus, I need to create an iframe that will be used as a hack to avoid this problem.
Of course, this is a really specific usage of iframe and only concern IE6...
Javascript WYSIWYG Editors use iframes, because that is easiest and best way to make it. For example TinyMCE uses it:
http://tinymce.moxiecode.com/
I was building a social network and i see iframes being useful for widgets to put on other peoples website to show like a mini profile or integrate with the content on a remote server. Seems like the most simple way to build this. I know some widgets use JavaScript. Also with the iframe method the session is the same as visiting the site like normal, so great for like buttons.
Many Formatted Text Editors (e.g. TinyMCE, HTMLArea) are implemented as iframe.
iFrames are okay for some cases, as X-domain-requests, or posting data to a source via parameters. But when I want to access data across domains, I prefer using CSS-files - they can accept params, set cookies, add content to the page (:before & :after) and give a visual feedback.
are there any reasons not to use iframes at all? I currently use it to load a page from a different server (a sign up page - part of a distributed application) to provide a seamless experience. Is using iframes considered bad practice or is its use OK?
The iframe is a great tool. It enjoys near-universal browser support, it's easy to implement and has a number of useful functions. As with any other HTML element, it can be abused, but wielded intelligently it can play a part in a solid UI.
Some developers might argue to use AJAX instead, and in some situations that may be the more appropriate approach, but AJAX is not a panacea and iframes can be a far simpler implementation which has the same end-result for your users. Do whatever is simplest first, and only change that when you can verify how and why that is not working.
Keep using iframes. Here's an example of why:
The whole Verified By Visa thing really annoys me. I'm happily shopping at some site that I trust, when I'm redirected to some site I've never heard of (not visa.com) and I have to fill in some other form and hope that I get redirected correctly back to the shopping site.
Then recently I was shopping at the John Lewis website, and they brought up the Verified By Visa page in an iframe - wonderful! I'm still looking at the John Lewis site, and all that's happening is I'm being asked for my Verified By Visa password - no problem.
Although as a web developer I know that there's no technical difference between that and a plain old redirect-there-redirect-back, the user experience is so much better!
Pros:
Helps with slow third-party content like badges and ads
Security sandbox
Download scripts in parallel
Cons:
Costly even if blank
Blocks page onload
Non-semantic
Source: Best Practices for Speeding Up Your Web Site
iframes have access to certain properties of the parent document, e.g. redirect the parent frame to a new location using parent.location.href or parent.window.location (IE allows to restrict that).
This is great for phishing attacks when embedding content from other servers (even if you trust that server it might be compromised).
iframes can also be used for a variety of other attacks: IFrames security summary.
With HTML 5 you'll be able to use the cross document messaging API to send messages from window to window, but for now the iFrame is the most viable alternative to any sort of AJAX that requires styling and scripting to load with the data.
If you're looking to just use text data in the iFrame, use AJAX instead. If you want external CSS or JavaScript to work in a protected environment, want styling to start from scratch, or need to access cross domain documents, use the iFrame.
Cons are that the accessibility of iFrames generally sucks, although you can prevent this by making sure that you proceed the iFrame with a notice of external content for screenreaders. Also check the HTML specifications for other ways to make the iFrame more accessible. Other than that and the obvious limitations scripting wise, the iFrame is a great tool is used responsibly and sparsely.
One last note, piling a page full of iFrames is definitely not a good idea, as remember that for each loaded iFrame, a DOM is created, HTML requests are made and document wrappers are instantiated, eating memory and bandwidth in the process. Keep iFrame's to a minimum on the page, and you'll avoid misuing a powerful tool in the HTML aresenal.
IFrames are a great way to "include" external content in a web page. However, there are a couple of (small) drawbacks:
Security sandboxing will cause problems with JavaScript if the IFrame does not originate from the same domain.
You cannot get CSS to co-operate between the IFrame and the parent page, unless you control the stylesheets themselves.
From an indexing point of view, the IFrame's content doesn't exist.
Screen readers might not like the IFrame, for the same reason. Or they won't be able to properly indicate the relative meaning of an IFrame's contents.
Apart from that, they're great! The points I mentioned might even be considered advantages, if you think about it (except the screen reader one): in principle, an IFrame can't influence its parent page's layout, and it isn't influenced itself by its parent either.
As a general rule, iframes are a bad experience for SEO reasons. So, you ask is there any reason not to use iframes? Yes, if you use iframes you are losing some organic placement in the search engines.
Of course, there are usability concerns which can (and should) trump SEO value of pages.
I'm looking for best-practices for designing a site that with accessibility in mind. The site is going to have a lot of older and less-abled individuals visiting it, and I want to make it as friendly for them as possible. Is there a resource that describes all the right tags, and attributes to use?
There are many many resources depending on your goals.
Strongly suggest you start with:
Section 508 (US legislation, obviously US centric though)
W3C's Web Accessibility Initiative and Web Content Accessibility Guidelines
edit:
Forgot to mention that WCAG has come in for some considerable criticism which makes this guy's efforts very helpful.
Also wanted to add, from personal experience, to remember that WA doesn't mean "blind people with screen readers". There are all manner of access limitations which you have to think of as well: e.g. dexterity issues related to e.g. muscle control, unusual input devices, and simple screen magnification.
Good luck!
Here's a quick list I tend to follow
Ensure it uses clean XHTML markup ideally to AAA standards,
Try where possible to spilt HTML, CSS, Javascript into respective files,
Create different style sheets for print, screen, etc.,
Ensure you take into consideration colours and fonts for the hard of sight and colour blindness,
Try to only place the main navigation at the top of the code so that the actual content appears near the top of the code, this way people do not have to scroll to far to see the content especially if they are using a screen reader / low res,
If you do have a lot of navigation before the content then place a link near the top allowing users to skip to the content,
Ensure the very first link on the page is to a text-only / low graphics version of the site,
Ensure ALL pages and all Essential functionality will work without JavaScript turned on,
There are lots of plugins for firefox to assist with development including:
Web Developer
No Script
HTML Validator
Firebug
Ensure the page renders across all browsers including old ones even if that means it works though does not match design exactly.
Ensure HTML, CSS, JavaScript is kept to the minimum file size to aid downloading times e.g. Remove white space and blank lines,
Always use LABELS in forms and alt, title tags in links and images,
Only use Tables for tabular data and ensure data appropriately labelled,
Where possible do not use JavaScript to write content to a page but use CSS to hide it, that way is JavaScript is disabled or does not work properly then content will still appear,
Always ensure you use onkeypress as well as onclick events in JavaScript encase the user can not / is not using a mouse.
Finally if you have to use blank images on a page for tracking etc. then don't give them Alt tags. This is my own view and is one which is hotly debated on-line especially when 1x1px images used to be used for spacing. However as far as I see it, if you are using a screen reader then you don't what it reading out stupid comments for images it does not need to see.
Try looking at Wikipedia's article on Web Accessibility. It contains lots of links to various sources of information for different countries, which may be useful depending on your target audience. The W3C was one of the original standards, but has plenty of critics.
Among other things.. provide "alt" and "title" attributes for every "img" tag.
Get a text-only browser like lynx. If your site works in lynx, it's likely to work for people who need screen readers or have other handicaps. It's no substitute for looking up the regulations, but it's a quick and easy check.
For another perspective, see the Dutch Government Web Guidelines.
The government provides a standard called section 508 that lays out what makes a site compatible.
A good resource is found at W3C site: Web Content Accessibility Guidelines.
A few things to keep in mind:
have a CSS link on each page that easily allows the font size to be changed.
Visually try to have appropriate presentation that is easy to read in a backwards S fashion.. left to right, back down.. etc..
ensuring that all the alt tags, etc, as mentioned in the other responses is vital.
see if there are some disability websites out there that specialize in testing your site. no harm in seeing what they list as being important to do.
make sure things are easy to read and find. this alone will make the job much easier.
There are many many resources on this topic. In fact, the danger is of information overload, rather than not enough information.
But an alternative approach is to think about your HTML page in generic terms, rather than the visual output you see in the web browser. If you wrote a piece of software that interpreted the website what would be helpful? This is a round-about way of saying use good semantics. My top tips would be to use standard XHTML for content and CSS for design. Also look up topics such as "progressive enhancement" and "behavioral Javascript".
But for resources:
The W3C's Web Accessibility Initiative: www.w3.org/wai
www.WebAIM.org
www.Accessify.com
www.CSSZenGarden.com for inspiration on how semantic markup can be styled to look very different.
It hasn't been mentioned yet so I figure I would mention it. If you want blind users to be able to use your site avoid flash. At the most 1% of flash I find on the internet is accessible.
A good list of resources about accessibility (colourblind screen-reader,typography etc) is here in design way.
For validation of web site and general documentation I use the W3C.
If you're developing in asp.net the opensource NAAK tool might be useful.
A must read is Jeffery Zeldman's "Designing with Web Standards"
Not sure if you are using Dreamweaver, but he has also just realeased a toolkit to validate your site for accessiblity.