My site has several ajax functions essentially identical (except different variable names, etc.) to the following:  function ajaxFunction(string) { var ajaxRequest;     try {         ajaxRequest = new XMLHttpRequest();     } catch (e) {         try {         ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");         } catch (e) {         try {             ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");         } catch (e) {                    alert("Your browser broke!");                 return false;         }         }     }//Anonymous function starts here ajaxRequest.onreadystatechange = function() {     if (ajaxRequest.readyState == 4) {             var ajaxDisplay = document.getElementById('div');             ajaxDisplay.innerHTML = ajaxRequest.responseText;     } } //and ends here     var QueryAjax = "?string=" + string;     ajaxRequest.open("GET", "AJAX_File.php" + QueryAjax, true);     ajaxRequest.send(null); }   For the indicated anonymous function, the javascript lint found at  warns me I should add a semicolon at the  end of this function (before the comment //and ends here in the code above) and that the function does not always return a value; the stricter lint found here:  warns me ajaxRequest.readyState == 4 should instead be ajaxRequest.readyState === 4.  Does anyone know how detrimental (if at all) the lack of semicolon and lack of "=== 4" are? Also, why does the function not always return a value? My site uses about 50 ajax functions similar to the one above and seems to perform great, but perhaps making these changes will speed up the execution of the functions? Any tips/advice would be greatly appreciated!
I'm using  to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value.length == 0 inside of an if statement.  Is there a performance benefit to replacing == with ===?   Any performance improvement would be welcomed as many comparison operators exist.  If no type conversion takes place, would there be a performance gain over ==?
I want to do the not independent sign in latex without having to install or define new commands (since I am using latexIT and I cannot load new packages).  Currently I use the following sign for independent:  X{\perp\!\!\!\perp}Y   What can I use for X not independent of Y?  I.e., something like this: ? Why do we focus so much in math on functions (as a subclass of relations)? Why is it that math so focuses on the subclass of relations known as functions? I.e. why is it so useful for us in nearly all branches of mathematics to focus on relations which are left-total and left-unique? Left- (or even right-) totality seem to be intuitive, since if an element doesn't appear in the domain, we might throw it out. But why left-uniqueness?  I'm looking for something like a "moral explanation" of why they would be the most useful subclass of relations.  My apologies if this is a previous question; I looked and didn't find much. In a tennis tournement of 128 players, elimination system, what is the probability that two twins will meet at some point? How to "find and replace" in a PDF on OS X? How to prevent Windows from entering idle state? How to disable all caches in safari 11? Enabling CORS in GeoServer (jetty)? I've got this one file, favicon.ico. It's actually a large group of nested files, but purely for example, just this one.  If I do cp favicon.ico favicon2.ico, Apache can read the second one just fine.  If I do mv favicon.ico favicon3.ico, Apache throws a 403 on favicon3.ico.  If I su apache, I can read the file as apache.  stat says both files are identical, except for the inode number.  Is there some hidden flag somewhere or something that I'm missing? I've never seen anything like this.  error_log says (13)Permission denied: access to /favicon3.ico denied Unique quadratic subfield of $\mathbb{Q}(\zeta_p)$ is $\mathbb{Q}(\sqrt{p})$ if $p \equiv 1$ $(4)$, and $\mathbb{Q}(\sqrt{-p})$ if $p \equiv 3$ $(4)$ I want to prove the assertion:      The unique quadratic subfield of $\mathbb{Q}(\zeta_p)$ is $\mathbb{Q}(\sqrt{p})$ when $p \equiv 1 \pmod{4}$, respectively $\mathbb{Q}(\sqrt{-p})$ when $p \equiv 3 \pmod{4}$.   My first attempt is this. In $\mathbb{Z}[\zeta_p]$, $1-\zeta_p$ is prime and $$ p = \epsilon^{-1} (1-\zeta_p)^{p-1} $$ where $\epsilon$ is a unit.  Since $p$ is an odd prime, $(p-1)/2$ is an integer and  $$ \sqrt{\epsilon p } = (1-\zeta_p)^{(p-1)/2} $$ makes sense and belongs to $\mathbb{Z}[\zeta_p]$.    How do I deal with the $\epsilon$ under the square root?  I guess the condition on the congruence class of $p$ comes from that.  Is this even the right way to proceed?  Uniqueness is not clear to me either.  I thought about looking at the valuation $v_p$ on $\mathbb{Q}$, extending it to two possible quadratic extensions beneath $\mathbb{Q}(\zeta_p)$, then seeing how those have to extend to common valuations on $\mathbb{Q}(\zeta_p)$, but I didn't see how to make it work.  I would appreciate some help. Bash 'unbound variable' error when variables are referenced in multiline comment (set -u) I have an unexpected behaviour- following snippet fail with 'unbound variable' error:  #!/bin/bash set -u &lt;&lt;EOF a=a b=$a EOF   Tested on:  GNU bash, version 4.4.12(1)-release  GNU bash, version 4.2.46(2)-release Reinstalling a fresh Windows 7 on a SSD while its original HDD version was upgraded to Windows 10 Many posts around that subject, but this case is a bit specific (I think) since it's not about a migration nor a cloning.   Initially Windows 7 on a 500GB HDD (OEM) then upgrade to Windows 10 (offered by Microsoft)   Now we have a brand new 550GB SSD and would like to install a fresh Windows  on it (and get rid of the old one on the HDD).   Do we have to install the initial (Win 7) or the upgraded (Win 10) on the SSD? What happens with the license, will Microsoft accept the license "transfer" automatically?   We'd prefer to install Windows 7, unless 10 is mandatory (or recommended).  Edit  Actually we'll go for win 10 since we need to switch languages after the install (thanks @Ramhound). Thus the question is back to the classical Win 10 reinstall, and is definitely a dupe . . . From A Classical Introduction to Modern Number Theory by Ireland and Rosen, page 33:     Corollary 1 (Euler's Theorem). If $(a,m) = 1$, then $a^{\phi(m)} \equiv 1\,(m)$.      Proof. The units in $\mathbb{Z}/m\mathbb{Z}$ form a group of order $\phi(m)$. If $(a,m) = 1$, $\bar{a}$ is a unit. Thus $\bar{a}^{\phi(m)} = \bar{1}$ or $a^{\phi(m)} \equiv 1\,(m)$.   If I'm interpreting this correctly, this proof implicitly uses the fact(?) that if $G$ is a group and $x\in G$, then $x^{|G|}=1$, where $1$ is the identity element of $G$.  If this is indeed true, can someone explain why? (I have had no prior exposure to group theory.) Blender build for Raspberry Pi3? How come such different methods result in the same number, $e$? If humans were able to catch all sun energy reaching the earth for their use, will the climate change? I guess that energy will be used up and, at the end, will contribute to heat the earth, so I see no big differences...  please explain your point of view. Are there rules for using manacles in combat? I can't quite find in the PHB or DMG how to slap manacles onto someone during combat. PHB 152 describes how to break out of mundane manacles, while DMG 165 shows how Dimensional Shackles work (they are essentially magic manacles -- use 1 action to bind an Incapacitated target).  Is there an official rule on how to use manacles in combat, or do we have to use house rules? I have recently been reading about Quantum Electrodynamics which I found very interesting, but even more confusing.  I understand photons mediate the electromagnetic force and interactions between charges can be described by virtual photon exchange. And that in Quantum Mechanics particles paths can be evaluated by sum over all paths...  An electron travelling from one point to another will take all paths, emitting and reabsorbing virtual photons. Does the electrons take all paths including those that involve faster than light velocities?  Is this question null, Does it mean anything to ask about properties of virtual particles?  Do I have the wrong idea about what virtual particles are? Incorrect plot using pgfplots (trigonometric functions like cos, sin and tan) I'm trying to plot a function with pgfplots for LaTeX. Unfortunately, pgfplots plots the function incorrectly.  Here is the LaTeX code I use:  \begin{figure}[H] \centering \begin{tikzpicture}     \begin{axis}[xlabel=Gameplays,ylabel=Rating]         \addplot+[gray,domain=1:30]         {0.5 + 0.5 * ((atan(x) * 2 / pi)^11.79)};     \end{axis} \end{tikzpicture} \caption{Omzetten van aantal gameplays tot impliciete rating} \label{fig:omzetten_impliciete_ratings} \end{figure}   Here is how the function should look like:     This is how it is plotted:    Does anyone know what I do wrong?  Thanks in advance! How do I get timestamp from e.g. 22-09-2008? The difference between a poor or meh question and a stellar question can often simply be someone understanding it and providing it a great answer. I can't begin to count the number of times I've justified re-opening a question as a moderator by saying:     Look at the answer it got, though. This isn't something we want deleted, this is something we want fixed, because it's obviously valuable. Someone with domain knowledge can easily edit that question based on the answer it received.   This doesn't only apply to borderline-poor or poor questions – sometimes a good edit means the difference between 100 and 10,000 people finding something through typing things into Google. Good titles are hard.   We think we've come up with a way to provide incentive for good, opportunistic edits to happen more often, ideally without questions needing to go through closure or collecting a centimeter of dust before they do. What if we simply rewarded folks that answered and edited questions with a special, relatively difficult to earn badge?  Let's say that you answer something, and:   You edit the question 12 hours before or after answering it. This allows you to edit now, answer later &mdash; or answer now and edit later, when you have the time. Your edit isn't rolled back, or outright rejected if it was a suggested edit The question is not closed for any reason, even simply being a duplicate Your answer has a score of 1 or higher   &hellip; then you've done something that we probably want to recognize. You understood something, you provided the knowledge that you have, and then you provided an edit to make sure that more people in need of this knowledge can find it, while raising the overall quality of the site.  Here's the proposed tiers for the badge (within the above stated criteria):   Explainer (Bronze): Answered &amp; edited 10  questions Refiner (Silver): Answered &amp; edited 50 questions Illuminator (Gold): Answered &amp; edited 500 questions   We think this is going to be pretty hard to game. You can't go leaving streaks of terse snark all over the place on questions you know are going to be closed anyway, and junk edits aren't going to fly.  We're talking about rewarding folks that take a tiny bit more time out of their day just to write a more descriptive title so that folks can find the awesome answer that they wrote. Just doing that alone can make a big difference. Sure, it's a tad hard to get at the gold level, but it's supposed to be. If you routinely edit questions that you answer and have done so for some time, you'd probably get it the day we roll it out.  While this is technically something that we came up with on the quality initiative ( | ) &mdash; this badge could be earned on all of our sites.  What do you think? What did we miss? What could be better about the idea?