I'm a beginner in servlet now I found that we would have to use in Java for servlet programming like this:  String docType =                 "&lt;!doctype html public \"-//w3c//dtd html 4.0 " +                         "transitional//en\"&gt;\n";   Now I want to know what's the benefit of that to use into programming? And also tell me that using of their advantages...  here is my program that I'm using this.  import java.io.*; import javax.servlet.*; import javax.servlet.http.*;  public class HelloWorld extends HttpServlet{      public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException{         response.setContentType("text/html");          PrintWriter out=response.getWriter();         String title="This is just a title and nothing except that..";         String docType =                 "&lt;!doctype html public \"-//w3c//dtd html 4.0 " +                         "transitional//en\"&gt;\n";          out.println(docType+         "&lt;html&gt;"+         "&lt;head&gt;&lt;title&gt;"+         title+         "&lt;/title&gt;&lt;/head&gt;"+         "&lt;body&gt;"+         "&lt;h1 align='center'&gt;"         +title+         "&lt;/h1&gt;"+         "&lt;ul&gt;"+         "&lt;li&gt;"+         "&lt;b&gt;First name: &lt;/b&gt;"+         request.getParameter("first_name")+"&lt;br&gt;"+         "&lt;b&gt;Last name: &lt;/b&gt;"+         request.getParameter("last_name")+         "&lt;/li&gt;"+         "&lt;/ul&gt;"+         "&lt;/body&gt;"         );     } }
What is DOCTYPE and why do I want to use it? What are the different DOCTYPEs I can use? What is the difference between standards and quirks mode, and what are some quirks I may run into with differently set DOCTYPEs?   Lastly, what is the proper DOCTYPE that I should be using?
I am working on a racing game in Unity3d and I have to show the rank as the winners touch the winning point.  As the winners reach at the winning point the image of the winner number should pop up for 1-2 seconds that is it.  How do I do it? Can anyone sort out this problem? Any help would be appreciated.  Thanks in advance :) Web sites can contain JPEG, GIF,PNG, SVG format graphics. Which ones should be used, and when? If I click to open achievements from a question when I click the X to close the achievements view I end up on the answers tab of the question, I assume because the X is over the tab and it's tapping through.    It appears if I hit the X it's ok, but if I tap anywhere else in the top row (where the X is) then I can switch to the question or answer tab. This is a phrase I've heard many people use, and it sounds wrong to me; e.g.:     The thing about that is, is that she might take it the wrong way.   It seems to treat "The thing [...] is"—the entire phrase—as the subject of the sentence. Of course, even if that were allowed, the comma placement would still be questionable.  I'm curious to know:   Is there a name for this wording? Is it specific to a certain dialect? Is its etymology known? When I play Black Ops 2, it seems that my xbox controller is inverted. Example: if I press up, my character looks down and vice versa. It was not like this before. Does anyone know how to reset the controller back to its original settings? There are lots (an infinitude) of smooth functions that coincide with $f(n)=n!$ on the integers. Is there a simple reason why Euler's Gamma function $\Gamma (z) = \int_0^\infty t^{z-1} e^{-t} dt$ is the "best"?  In particular, I'm looking for reasons that I can explain to first-year calculus students. Does the proof of Bolzano-Weierstrass theorem require axiom of choice? Is it possible to make a sequence of renders and give the user the option to cancel the process through the UI at any given time? How do I set up a Cron job? Should we allow adding rep to bounties to extend their duration? There are a few variables here that I was thinking about:   Spend rep to extend a bounty for a certain amount of time Allow the rep spent to extend duration to add into the original bounty Create minimums on the amount necessary to extend dependent on how long it has been up   These are just ideas and can be tweaked as necessary, but the idea in whole is to encourage people to spend more on rep and avoid "wasted" rep because there wasn't a good answer to a question while minimizing the amount of possible abuse. This was part of the idea to spend a small amount of rep to extend duration without adding to the rep so that you wouldn't have to spend the whole amount over again for a couple more days.  The typical use case that I am thinking of is when you create a bounty and it still gets no attention. I think it would be cool if you could then add onto it to turn it into a higher bounty instead of having those points completely gone.  Possible abuses:   Keeping bounty questions alive for inappropriately long times. There is already an answer but the author does not want to award the bounty.   For 1, you can resolve this by increasing the amount necessary to keep a question alive exponentially similar to what is already in place. You could also halve the amount of extended duration per extension. For 2, this is a problem with the existing system as well, but the author does not have a positive incentive not to award the points since he himself still cannot get them back. Let's say I have the domain johnsmith.com and I want people to reach me via email, what is the best email username to use?  Some examples:   john@johnsmith.com - redundant john.smith@johnsmith.com - redundant and looks kinda stupid mail@johnsmith.com - makes sense, but looks very "technical" me@johnsmith.com root@johnsmith.com - for the geeks among us ;-)   Of course, technically I can simply say that I will be able to receive *@johnsmith.com, however, for a better user experience I still just want one email address for public presence (website, business cards, etc.).  Any suggestions? I would like footnote numbering to continue over pages and chapters. In my document it's reset every chapter. I'm using the report documentclass. How do I avoid rendering glitches from overlapping faces? A generic question across most board games: once a player has taken their turn (taken their finger off the piece they are playing), should they be allowed to change their mind?  Similarly, if a player forgets to take a privilege, such as an occupied building in Puerto Rico giving an extra worker, or plantation, if they remember a few moves later, should they be allowed to take the privilege?  Very few rules explicitly express how these events should be dealt with, so they are generally left up to the group. However, my group's rules will change depending on the personality of the players playing (not all members are available each time we play). I would like to make this consistent, and would appreciate feedback on how others deal with this scenario. Capacitance of a single charged plate? Lets say we have a single plate that has a charge of $+Q$ on it. A plate with charge $-Q$ is infinite distance away. Will the plate with $+Q$ have a capacitance associated with it? Why or why not? I was thinking that because the distance between the plates is infinity, the capacitance is zero, but according to my TA, that is not the case. There is always some sort of "absolute" capacitance for the plate with $+Q$ (a capacitance will exist between the plate and air?). Can someone help me out in understanding this? A guide to moderating chat Chat is an offshoot of the main site, and using it is  during their time here.  Chat is our place for:        Real-time collaboration   Meeting fellow members of the community   Less structured, casual (but still roughly on-topic) conversation      Our chat system exists to serve the main site; users of each site can gather and commune with each other.  When in chat, we expect all users to abide by our  policy, which means that we expect community members to treat each other with respect.    While it is a place where the community can go to interact on a more casual level, chat still needs to be moderated by the community and there are tools in place to help with the moderation. This raises a few questions, that are addressed here: Developer Accounts for ExactTarget How to replace the domain name in a Wordpress database? I have a Wordpress database which was installed in a development environment... thus, all references to the site itself have a fixed IP address (say 192.168.16.2). Now, I have to migrate that database to a new Wordpress installation on a hosting. The problem is that the SQL dump contains a lot of references to the IP address, and I have to replace it with: my_domain.com.  I could use sed or some other command to change the that from the command line, the problem is that there are a lot of configuration data which uses JSON. So what? Well, as you know, JSON arrays uses things like: s:4: to know how many chars an element has, and thus, if I just replace the IP with the domain name, the configuration files will get corrupted.  I used an app for Windows some years ago that allows to change values in a database and takes care of the JSON arrays. Unfortunately, I forgot the name of the app... so the question is: do you know any app that allows me to do what I want? Challenges with Key with Gaps? I had a mistake with a trigger which resulted in errors in PostgreSQL 9.4.3 on x86_64-unknown-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit.  Each time during the error, the primary key of SERIAL increased.  After fixing the bug, the table measurements is    measurement_id | measurement_size_in_bytes |             time               ----------------+---------------------------+-------------------------------               1 |                     77777 | 2015-07-14 18:29:56.858703+03               2 |                       888 | 2015-07-14 18:29:56.882552+03               3 |                       888 | 2015-07-14 18:30:15.505957+03               4 |                       888 | 2015-07-14 18:41:01.878106+03              39 |                     77777 | 2015-07-15 12:11:21.21391+03              40 |                     77777 | 2015-07-15 12:11:59.551973+03              41 |                     77777 | 2015-07-15 12:12:05.48982+03              42 |                     77777 | 2015-07-15 12:13:02.402053+03              43 |                     77777 | 2015-07-15 12:13:02.419412+03              44 |                       888 | 2015-07-15 12:13:02.434728+03          ...   where the amount of error statements has been 35 (= 39-4).  This jump in IDs may become a challenge later when I want to integrate this table with a partial index where order matters.   Table  CREATE TABLE measurements     (         measurement_id SERIAL PRIMARY KEY NOT NULL,         measurement_size_in_bytes INTEGER NOT NULL,         time TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,         CONSTRAINT no_duplicate_measurements UNIQUE (time)     );       What are the challenges of keys with gaps? Let $F$ be a field and $F^\times$ be its group of units. If $F^\times$ is cyclic, then show that $F$ is finite.  I'm a bit stuck. I know that I can represent $F^\times = \langle u \rangle$ for some $u \in F^\times$ and that we must have that $|F^\times| = o(u)$, where $o(u)$ denotes the order of $u$ in $F^\times$.  I tried assuming $o(u) = \infty$, but I'm not sure exactly where to go from there. I was wondering if I could get a hint.