How Much Support Is There for -Webkit-Overflow-Scrolling:Touch

How much support does GWT have for Java layout managers?

GWT layout support is done through subclasses of 'Panel'. Some of them like 'DockPanel' behave a little bit like Swing layouts (BorderLayout) but there's no way you'll ever be able to take Swing code and compile it into GWT.

This is a common mis-understanding when it comes to GWT. It's written in Java solely because Java is statically type and widely supported with world class editors. The fact that it's written in Java has nothing to do with any desire by the GWT team to allow you to port SWT/AWT/Swing to GWT. The web is a different environment to the desktop, and since your code ends up compiled into javascript it would never make sense to take any kind of Java Desktop application and hit the convert button. That's what Applets tried to do many years back...and we all know how that turned out ;)

How many international languages does the iPhone Simulator support?

I reinstalled the SDK/Xcode and got all 40 of them back.

(was 18, but now it's more)

How to find the minimum support in Apriori algorithm

The support and confidence are measures to measure how interesting a rule is.

The minimum support and minimum confidence are set by the users, and are parameters of the Apriori algorithm for association rule generation. These parameters are used to exclude rules in the result that have a support or a confidence lower than the minimum support and minimum confidence respectively.

So to answer your question, when you say that: "For an example when support and confidence is given as 60% and 60% respectively what is the minimum support?" you probably mean that you have set the minimum support and confidence to 60 %.

I think that you are just confused by the terms.

What is the maximum possible length of a query string?

RFC 2616 (Hypertext Transfer Protocol — HTTP/1.1) states there is no limit to the length of a query string (section 3.2.1). RFC 3986 (Uniform Resource Identifier — URI) also states there is no limit, but indicates the hostname is limited to 255 characters because of DNS limitations (section 2.3.3).

While the specifications do not specify any maximum length, practical limits are imposed by web browser and server software. Based on research which is unfortunately no longer available on its original site (it leads to a shady seeming loan site) but which can still be found at Internet Archive Of Boutell.com:

Microsoft Edge (Browser)

The limit appears to be around 81578 characters. See URL Length limitation of Microsoft Edge
Chrome

It stops displaying the URL after 64k characters, but can serve more than 100k characters. No further testing was done beyond that.
Firefox (Browser)

After 65,536 characters, the location bar no longer displays the URL in Windows Firefox 1.5.x. However, longer URLs will work. No further testing was done after 100,000 characters.
Safari (Browser)

At least 80,000 characters will work. Testing was not tried beyond that.
Opera (Browser)

At least 190,000 characters will work. Stopped testing after 190,000 characters. Opera 9 for Windows continued to display a fully editable,
copyable and pasteable URL in the location bar even at 190,000 characters.
Microsoft Internet Explorer (Browser)

Microsoft states that the maximum length of a URL in Internet Explorer is 2,083 characters, with no more than 2,048 characters in the path portion of the URL. Attempts to use URLs longer than this produced a clear error message in Internet Explorer.
Apache (Server)

Early attempts to measure the maximum URL length in web browsers bumped into a server URL length limit of approximately 4,000 characters, after which Apache produces a "413 Entity Too Large" error. The current up to date Apache build found in Red Hat Enterprise Linux 4 was used. The official Apache documentation only mentions an 8,192-byte limit on an individual field in a request.
Microsoft Internet Information Server (Server)

The default limit is 16,384 characters (yes, Microsoft's web server accepts longer URLs than Microsoft's web browser). This is configurable.
Perl HTTP::Daemon (Server)

Up to 8,000 bytes will work. Those constructing web application servers with Perl's HTTP::Daemon module will encounter a 16,384 byte limit on the combined size of all HTTP request headers. This does not include POST-method form data, file uploads, etc., but it does include the URL. In practice this resulted in a 413 error when a URL was significantly longer than 8,000 characters. This limitation can be easily removed. Look for all occurrences of 16x1024 in Daemon.pm and replace them with a larger value. Of course, this does increase your exposure to denial of service attacks.

Can HTTP POST be limitless?

EDIT (2019) This answer is now pretty redundant but there is another answer with more relevant information.

It rather depends on the web server and web browser:

Internet explorer All versions 2GB-1

Mozilla Firefox All versions 2GB-1

IIS 1-5 2GB-1

IIS 6 4GB-1

Although IIS only support 200KB by default, the metabase needs amending to increase this.

http://www.motobit.com/help/scptutl/pa98.htm

The POST method itself does not have any limit on the size of data.

Is there any reason to use the support.v4 library in Android?

There are a number of features unique to the support library that apply to all API levels:

LocalBroadcastManager - Allows applications to easily register for and receive intents within a single application without broadcasting them globally.
ViewPager - Adds a ViewGroup that manages the layout for the child views, which the user can swipe between.
DrawerLayout - Adds support for creating a Navigation Drawer that can be pulled in from the edge of a window.
SlidingPaneLayout - Adds widget for creating linked summary and detail views that appropriately adapt to various screen sizes.
FileProvider - Adds support for sharing of private files between applications.

And others such as

WakefulBroadcastReceiver - Helper for the common pattern of implementing a BroadcastReceiver that receives a device wakeup event and then passes the work off to a Service, while ensuring that the device does not go back to sleep during the transition.
AtomicFile - for atomic operations on a file
SwipeRefreshLayout - adds pull to refresh to a view

Also note that some newer features, such as nested Fragments (which were added only in Android 4.2) are available in the support library versions of Fragments. Renderscript intrinics were also only introduced in Android 4.2 and important if you are doing things such as real time image processing. Big style notifications and notification actions (introduced in Android 4.1) are much easier to work with when using NotificationCompat (and the Android Wear Notification API is built on it).

What is the maximum length of a URL in different browsers?

Short answer - de facto limit of 2000 characters

If you keep URLs under 2000 characters, they'll work in virtually any combination of client and server software.

If you are targeting particular browsers, see below for more details on specific limits.

Longer answer - first, the standards...

RFC 2616 (Hypertext Transfer Protocol HTTP/1.1) section 3.2.1 says

The HTTP protocol does not place
any a priori limit on the length of
a URI. Servers MUST be able to handle
the URI of any resource they serve,
and SHOULD be able to handle URIs of
unbounded length if they provide
GET-based forms that could generate
such URIs. A server SHOULD return
414 (Request-URI Too Long) status if a
URI is longer than the server can
handle (see section 10.4.15).

That RFC has been obsoleted by RFC7230 which is a refresh of the HTTP/1.1 specification. It contains similar language, but also goes on to suggest this:

Various ad hoc limitations on request-line length are found in
practice. It is RECOMMENDED that all HTTP senders and recipients
support, at a minimum, request-line lengths of 8000 octets.

...and the reality

That's what the standards say. For the reality, there was an article on boutell.com (link goes to Internet Archive backup) that discussed what individual browser and server implementations will support. The executive summary is:

Extremely long URLs are usually a
mistake. URLs over 2,000 characters
will not work in the most popular web
browsers. Don't use them if you intend
your site to work for the majority of
Internet users.

(Note: this is a quote from an article written in 2006, but in 2015 IE's declining usage means that longer URLs do work for the majority. However, IE still has the limitation...)

Internet Explorer's limitations...

IE8's maximum URL length is 2083 chars, and it seems IE9 has a similar limit.

I've tested IE10 and the address bar will only accept 2083 chars. You can click a URL which is longer than this, but the address bar will still only show 2083 characters of this link.

There's a nice writeup on the IE Internals blog which goes into some of the background to this.

There are mixed reports IE11 supports longer URLs - see comments below. Given some people report issues, the general advice still stands.

Search engines like URLs < 2048 chars...

Be aware that the sitemaps protocol, which allows a site to inform search engines about available pages, has a limit of 2048 characters in a URL. If you intend to use sitemaps, a limit has been decided for you! (see Calin-Andrei Burloiu's answer below)

There's also some research from 2010 into the maximum URL length that search engines will crawl and index. They found the limit was 2047 chars, which appears allied to the sitemap protocol spec. However, they also found the Google SERP tool wouldn't cope with URLs longer than 1855 chars.

CDNs have limits

CDNs also impose limits on URI length, and will return a 414 Too long request when these limits are reached, for example:

Fastly 8Kb
CloudFront 8Kb
CloudFlare 16Kb

(credit to timrs2998 for providing that info in the comments)

Additional browser roundup

I tested the following against an Apache 2.4 server configured with a very large LimitRequestLine and LimitRequestFieldSize.

Browser     Address bar   document.location
                          or anchor tag
------------------------------------------
Chrome          32779           >64k
Android          8192           >64k
Firefox          >64k           >64k
Safari           >64k           >64k
IE11             2047           5120
Edge 16          2047          10240

See also this answer from Matas Vaitkevicius below.

Is this information up to date?

This is a popular question, and as the original research is ~14 years old I'll try to keep it up to date: As of Jan 2021, the advice still stands. Even though IE11 may possibly accept longer URLs, the ubiquity of older IE installations plus the search engine limitations mean staying under 2000 chars is the best general policy.

How Many Network Connections Can a Computer Support?

Dan Kegel put together a summary of techniques for handling large amounts of network connections from a single server, here: http://www.kegel.com/c10k.html