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i am reading about HTML-5 and what are the new features it offers, and one of these features are the App Cache which is define in W3school website as "Offline browsing - users can use the application when they're offline",,.
But is this really a new feature in HTML-5 that was not avilable in earlier HTML versions?? since from long time (at least 6 years back) we have the option of browsing a web site even if we are offline since the HTML will be cached inside the browser ?? so what is meant by offline browsing in HTML-5??
BR
Yes, this is new functionality introduced with HTML5. This is not the same as your browser caching the site, such as the ole "save for offline use" option.
Some browsers offline caching mechanisms are simply just unreliable. HTML5 instead uses a manifest file to tell the browser what it should use for offline storage.
See:
http://www.html5rocks.com/en/tutorials/appcache/beginner/
And the w3c working draft:
http://www.w3.org/TR/html5/offline.html
My favourite HTML5 resource (more regarding correct usage of older elements, and how to use the new ones): http://html5doctor.com/
Lastly, as many experienced web developers will tell you, w3schools is trouble. They're infamous for having all kinds of misleading and false information. See http://w3fools.com/
Hope this helps.
Related
This is probably a silly question, however: from a Web Design/Development point of view (I mean support for web standards and web technologies), could Google Chrome and Chromium be considered equivalent?
I know that they are essentially the same browser, the former being the branded version of the latter, but they also have some functional differences, and Google Chrome features some additions not present in the base Chromium browser (detailed on the Chromium page on Wikipedia).
They use the Blink engine, which is in turn also used by other Chromium-based browsers like MS Edge and Opera; and all these browsers have an uneven support for many different web technologies, as detailed on https://caniuse.com.
I'm working on a Linux machine, and my distro ships Chromium by default, providing it from its standard repo; for the sake of simplicity and keeping things clean, I would prefer to avoid adding another external repo and install Chrome just for this task, if I can rely Chromium to behave exactly the same and not have any compatibility issue.
Like I said, this question is probably silly, but given the differences between other Chromium-based browsers, maybe this doubt of mine could be justified.
EDIT: Please note that I'm not interested in the differences between Google Chrome and Chromium from an user point of view or in details of their history and so on; I only wish to know if from a website development point of view, they are fully compatible or if they support the same set of features. In other words, if I test a site from Chromium, can I be sure that it will work also in Google Chrome? Do they support the same exact set of CSS, JS (and other web-related technologies) features?
Chromium is an open-source browser project that forms the basis for the Chrome web browser. It's maintained by the Chromium Project, while Chrome is maintained by Google. Aside from code-opennes, the main difference (for your concerning question) between the two browsers is that Google adds a number of proprietary features to Chrome like automatic updates and support for additional video formats. Also added is AAC, H.264, and MP3 support. Giving you acess to a wider variety of media content, like sites using HTML5 to stream H.264 videos. Both browsers include Opus, Theora, Vorbis, VP8, VP9, and WAV codecs. Chrome also includes a sandboxed Adobe Pepper API (PPAPI) Flash plug-in that updates along with.
From a programmatic side, both support Google DevTools protocol with all of the flexibility and possibilities this brings, like browser automation using the popular puppeteer Node.js runtime, allowing you to run automated tests either in head or headless environments. Both browsers use the Blink rendering engine and the V8 JavaScript engine, so both will give you same support for CSS, HTML and DOM parsing/rendering, and same JavaScript compatibility, functionality and performance. So the real difference is if you're developing media-content centric web apps, in that case you will benefit more from Chrome since it includes all of the above mentioned extra plugins and supported formats, all of this makes the web more accessible to it and provides a wider range of things you could do.
We are developing a rich single page web application by using requirejs, jquery and knockout. At early stages of our development we have missed the first and fore most HTML below doc type tag
Now after an year we realized this. Our application is targeted only on Chrome 18 version as our user machines have only Chrome 18.
Based on initial analysis and study we learned following points
1. Not having doctype can cause browser to render the document in quirks mode and not standard mode.
2. Quirks mode browser look and feel may be unpredicted and browser needs to work hard in order to render the page.
3. Chrome has quirks mode. Please refer the url (https://en.wikipedia.org/wiki/Quirks_mode)
But at the same time We came to know from stack exchange post(Can you use HTML5 features without declaring the HTML5 DOCTYPE?).
- Webkit-browsers, Firefox and Opera will handle HTML5 elements quite normally even if your doctype is not HTML5
After reading stack exchange post, We are little confused. Now my question is
Omitting Doc type in our application cause to suffer our application any kind of penalties or negative impacts in terms of performance and memory leaks in Chrome 18 browser.
Even though if we don't have any penalties, having Doc type has provides any merits to our application in terms of performance and memory leaks in Chrome 18 browser.
More Info Based on Comments:
1. When I say penalties it is not about SEO issues. It is about performance and memory leaks etc...
2. We have done initial sanity tests and we see every thing is functional as expected. But unable to test performance and memory leak penalties.
3. Our application is intranet application and it is accessible only from our intranet net work.
I want to make a html-based document which I'm going to distribute through the Internet.
Under certain situations, people don't have the internet access, and I want to make it available even under off-line circumstances. So, I'm planning to:
distribute an off-line version of the html-based document, and
keep its up-to-date version on the http server
I want people to see the up-to-date version of the document if possible. So, I want to redirect the readers of the off-line version to the up-to-date version if they have an access to the Internet.
Is there any way to do this?
Thanks in advance.
Note: We can check whether a reader of a web page have an access to the Internet using JavaScript, but we cannot use this trick from a local html page unless we explicitly disable the security features of browsers. This trick is basically to check whether a reader still has an access to the Internet like they had when they loaded the web page.
is there any list which HTML5 features the UIWebView supports and which not? I am interested mainly in:
1) localStorage/sessionStorage
2) offline manifest
3) web sockets
4) web workers
In pre-iOS4 there was not an offline manifest support, which was necessary to program in objective-C, which - when done broke the localStorage support, since the UIWebView does not allow sharing localStorage content between pages accessed online and pages manually downloaded and stored in the file system, because the URL was different
Thanks a lot
BR
STeN
The right answer ought to be caniuse.com which is currently the best site for non-mobile browser info. From what I've found there is no other site which has this sort of information. I would encourage you to encourage the maintainer of caniuse.com to add mobile browser information. You can do that by posting here:
http://a.deveria.com/?p=82#comments
Can HTML and javascript run offline like an application? I'm looking to running the webpage offline like silverlight OOB applications. But if the browser closes, I want some way to run the webpage again without going online. Is this possible?
The HTML 5 draft introduces mechanisms for a webpage to be used as an offline application although, obviously, as a recent draft spec this isn't supported by all browsers.
You can also File > Save As and just save an HTML file and its associated JS locally.
Google Gears provides the kind of functionality that you're looking for. Google themselves are planning on phasing it out in favour of HTML5's draft (see David's response) but I think you will find Gears more mature [for the time being, at least], and (perhaps importantly, if you're considering redistribution) more consistent across different browsers.
[Further edit:] The Adobe AIR runtime allows you to run HTML and JavaScript applications on the desktop.