Click function doesn't work on a new added class I have a button that adds newClass to the parent div when clicked and it also shows another button. The next thing that I want to make is to display some text with a click function on .newClass .display-info.  All the answers that I've found refer to the jQuery .live method, but this is deprecated. Instead I used .on method but without any result...  This is the example code:    HTML:  &lt;div class="parent"&gt;   &lt;button class="btn-click"&gt;     Click me   &lt;/button&gt;    &lt;button class="display-info"&gt;     Show text   &lt;/button&gt;   &lt;span class="show-this"&gt;Text to be displayed&lt;/span&gt; &lt;/div&gt;     JS:  $('.btn-click').click(function() {     $(".parent").addClass('newClass');   $(".display-info").show(); });  $('.newClass .display-info').on("click",function() {     $('.show-this').show(); });   CSS:  .display-info, .show-this {   display:none; }
Event binding on dynamically created elements? I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.
Who is blowing the horn to alert the Night's Watch? What makes a field not groupable I'm trying to use an aggregate query, but one of the fields I want to group by is not groupable (saw it in the soql error and then verified groupable=false in the metadata).  It's just a number field that holds an integer (number 2,0 in salesforce field spec-speak).  Is there a trick to make it groupable?  Any way around this problem? I don't want to write hundreds of lines of code just to average a list by this field. This is the problem I am currently having trouble with:  If $\lambda_1$ and $\lambda_2$ are eigenvalues of matrix  $$         \begin{bmatrix}         a &amp; b\\         c &amp; d\\         \end{bmatrix}$$prove that $\lambda_1^2$, $\lambda_1\lambda_2$ and $\lambda_2^2$ are eigenvalues of matrix $A$.     $$A=\begin{bmatrix}     a^2 &amp; ab &amp; b^2\\     2ac &amp; ad+bc &amp;2bd\\     c^2 &amp; cd &amp;d^2\\     \end{bmatrix}$$  What have I considered so far:   I tried to find characteristic polynomial of first matrix and then find the roots which would be $\lambda_1$ and $\lambda_2$. I was hoping I can make a connection with characteristic polynomial of matrix $A$, but it got too complicated and did not seem like the right idea. Since there are two eigenvalues for first matrix, there are two eigenvectors. I thought about somehow using $A\vec v_i=\lambda_i\vec v_i$, where $i=1,2$  Also, I thought about finding a connection between these two matrices. What I see is that the sum of elements of first and second column, of first matrix, are $(a+c)$ and $(b+d)$, respectively.  Sum of first, second and third column of matrix $A$ are $(a+c)^2, (a+c)(b+d)$ and $(b+d)^2$. Now, if I could assign $\lambda_1$ and $\lambda_2$ to $(a+c)$ and $(b+d)$, then I would get that sum of first, second and third column of matrix $A$ are $\lambda_1^2$, $\lambda_1\lambda_2$ and $\lambda_2^2$, but what would be next?   I thought it would be good to combine 2. and 3rd idea, but I am not making any progress.  I appreciate any help. What solutions does the equation $4x\equiv2\mod10$ have? (Hint, it will have more that one.) What about solutions to an equation $ax\equiv d\mod n$, where $d=\gcd(a,n)$?  This is the question that appeared in our universities last year paper. But it seems very difficult for me like for first part I am able to solve by simplifications I got $x=5\cdot Z +3$ as solution which makes sense and seems fair but for the second one, I have no idea how can I approach that. Can you please help me out with that one. I tried to simplify that by using Euclidean algorithm but still, I didn't get any idea that what actually the solution will be. My final exam is on 2nd of next month and because of covid I am unable to contact in person for any help. So any help from this site will be appreciated. Thank you for looking at this question! How can I know if $2^{2^{2^{2^{2}}}}+1=?$ is prime? reference overlay numbers with names How to copy some, but not all files? How can I avoid Java code in JSP files, using JSP 2? I have been getting this question lately from students and although I have a lot of information to offer, I have not found a source that I can point people to where they can read an update answer (I have found a lot of misinformation and obsolete information). So, some of the questions I have for package formats like snap, appimage, flatpak and others in this evolution of universal packaging systems are:   Who created the package format? What features does it offer? What features are unique to it? (That the others do not yet have) Who supports it? What Distributions use it? What focus does the package have? (For Desktop, Clouds, Mobile, etc..) Which are more actively developed? There appears to be a giant security vulnerability with Android that seems to basically affect all phones.  wrote:  The vast majority of Android phones can be hacked by sending them a specially crafted multimedia message (MMS), a security researcher [Joshua Drake] has found. ... Drake found multiple vulnerabilities in a core Android component called Stagefright that’s used to process, play and record multimedia files. Some of the flaws allow for remote code execution and can be triggered when receiving an MMS message, downloading a specially crafted video file through the browser or opening a Web page with embedded multimedia content. ... The MMS attack vector is the scariest of all because it doesn’t require any interaction from the user; the phone just needs to receive a malicious message. For example, the attacker could send the malicious MMS when the victim is sleeping and the phone’s ringer is silenced, Drake said. After exploitation the message can be deleted, so the victim will never even know that his phone was hacked, he said.  What can a regular user do to mitigate the issue? Disable Google Hangouts? Suppose that X and Y are independent Poisson distributed values with means $\theta$ and $2\theta$, respectively. Consider the combined estimator of $\theta$ $$ \tilde{\theta} = k_1 X + k_2 Y $$ where $k_1$ and $k_2$ are arbitrary constants.   Find the condition on $k_1$ and $k_2$ such that $\tilde{\theta}$ is an unbiased estimator of $\theta$. For $\tilde{\theta}$ unbiased, show that the variance of the estimator is minimized by taking $k_1 = 1/3$ and $k_2 = 1/3$. Given observations $x$ and $y$ find the maximum likelihood estimate of $\theta$ and hence show that $\tilde{\theta}$ is also the maximum likelihood estimator.   I have gotten (1) and (2) okay, but it's (3) I am having trouble with, I'd be okay if $X$ and $Y$ had the same parameter but I'm having trouble with $X$ and $Y$ having different parameters, any help would be appreciated.   NOTE   For (1) I got $k_1 = 1 - 2k_2$.   For (2) I found the variance of $\tilde{\theta}$, then differentiated and let equal to zero to minimize - therefore we get (after subbing in $k_2 = 1 - k_1/2 $) $$3k_1-1=0,$$ which when subbing in $1/3$, we see it is minimised.   Thank you. Uk tourist visa - duration of stay My mother is given a UK tourist visa for 2 years with a duration of stay as 180 days. It is a c type multiple entry visa. Is this 180 days is the total stay she can take or is it duration of stay per visit.  Thanks in advance for your reply. I'm having a bit of a trouble with the below question     Given $G$ is an undirected graph, the degree of a vertex $v$, denoted by $\mathrm{deg}(v)$, in graph $G$ is the number of neighbors of $v$.   Prove that the number of vertices of odd degree in any graph $G$ is even. Make voting activity on your posts available on site metas (what you would get from rep if metas had rep) Child metas don't have rep, so there's no point in tracking a rep stat or reporting changes.  But one of the things rep updates do on main sites is to alert me when there's activity on older posts.  On metas, unless I revisit a question I'll never notice that there's been a bunch of voting (which might be accompanied by new comments that didn't ping me).  I'd like to know about that activity, not because of any ego reasons but because meta is where site policies get discussed and set and it's useful to know about changes in the community will.  A couple days ago I visited a meta post where, a few weeks ago, my answer had been voted down, and this time it was at the top.  Could we have something like the reputation-changes tab on meta?  I suspect that the data already exists, because I once  (and I see I'm not the only one).  If something akin to reputation is already being tracked internally on per-site metas, can we get it exposed? Is the Star Wars Universe just one galaxy? Out-of-control starship results in some crew members landing in a rebirthed universe? How / can you connect Ethernet devices together without magnetics? How do you wire it up? What sorts of practical limitations are there on doing this?  To clarify, I'm not trying to connect two computers here. I'm thinking specifically of creating a small network of microcontrollers on a single board. Lets say the total length of a network segment is no longer than 6 inches. This would be for 10BaseT or at most 100BaseT. Is it possible to legally visit uninhabited islands in the Pacific for a couple of days/weeks like Robinson Crusoe Do you know any way how can I visit uninhabited islands in the Pacific (French Polynesia, Micronesia etc.) and stay there for a couple of days or weeks?  The only condition, these island (or islands) should have drinking water.  Could it be done legally or only illegally?  Does any company do such crazy things via plane or boat?  Any information is appreciated.  I am mostly interested in French Polynesia.  Boat or plane... that's not very important. Deducing $\sin x + \cos x \ge 1$ from $(\sin x + \cos x)^2 = 1 + 2 \sin x \cos x$ So in trig, say I have an acute angle $X$. And one can intuitively conclude that $\sin x + \cos x \ge 1$, but how does the fact that $$(\sin x + \cos x)^2 = 1 + 2 \sin x \cos x$$ tell me that it is true that $\sin x + \cos x \ge 1$? I don't quite see the connection. Thanks django manytomanyfield .add() method