I have array checkbox (category) and I want to display list of checkbox size if one of them is being checked. I have already made the JavaScript but it didn't work out. Here's my code: View @foreach ($categories as $category) &lt;div class=&quot;mb-0 ml-2&quot;&gt;  &lt;label class=&quot;mb-0&quot;&gt;   &lt;input class=&quot;category mb-0&quot; id=&quot;category&quot; name=&quot;category[]&quot; type=&quot;checkbox&quot; value=&quot;{{ $category-&gt;id }}&quot; onChange=&quot;this.form.submit()&quot;    @if (in_array($category-&gt;id, $checkedCat)) checked @endif&gt;   {{ $category-&gt;name }}  &lt;/label&gt; &lt;/div&gt; @endforeach  &lt;div id=&quot;size&quot; class=&quot;sizefilter&quot;&gt; //List of size checkbox &lt;/div&gt;  JavaScript $(&quot;#category&quot;).on('change', function() {  if($('input[name=&quot;category[]&quot;]:checked'))  {     $(&quot;.sizefilter&quot;).show();  } else  {     $(&quot;.sizefilter&quot;).hide();  } });
How can I check the existence of an element in jQuery?  The current code that I have is this:  if ($(selector).length &gt; 0) {     // Do something }   Is there a more elegant way to approach this? Perhaps a plugin or a function?
Can I run PC steam games on a Mac? Find the limit of $\sum\limits_{k=1}^n\left(\sqrt{1+\frac{k}{n^2}}-1\right)$ What are the alternative Android app markets? How many competing Android markets (other than the Play Store itself) are there and are they any good?  Which ones do you use and why? Is there a schematic overview of Ubuntu's architecture? as enthusiastic, advanced Linux learner, I'd love to get an overview about Linux' architecure/structure in general. You know, like "the big picture".  I'm thinking of a large schematic graphic showing what is what, who is who, what system (e.g. X) comprises which subsystems (GDM/Gnome/Compiz) on the way from a to z, from boot to interactive desktop, including the most important background services (auth, network, cron, ...).   Maybe a bit like this:  but way more detailed. There's bootchart, which produces very comprehensive charts, but they again are too detailed and difficult to get the "big picture" from.  Is there such a thing? Possibly not for the whole System, but maybe for single subsystems?  I had trouble searching for this, because using search terms like "scheme" or "architecture" pointed to the wrong direction (a tool called "scheme" or CAD software for linux).  I appreciate any links. If there's interest in those schematic overviews and links, maybe someone could turn this post into a wiki post? Proteins are synthesized on ribosomes from mRNA copies of regions of the DNA. But ribosomes themselves are made up of proteins (and RNA). So how could the first ribosomes have arisen? Was there previously some other way of making proteins other than by ribosomes and mRNA? How to detect Windows 64-bit platform with .NET? In a  2.0 C# application I use the following code to detect the operating system platform:  string os_platform = System.Environment.OSVersion.Platform.ToString();   This returns "Win32NT". The problem is that it returns "Win32NT" even when running on Windows Vista 64-bit.  Is there any other method to know the correct platform (32&nbsp;or 64&nbsp;bit)?  Note that it should also detect 64&nbsp;bit when run as a 32&nbsp;bit application on Windows 64&nbsp;bit. Rest mass of the photon Why is the rest mass of the photon is taken to be zero?  If rest mass of the photon is non zero, then it leads to infinite energy of the photon (by $E=mc^2$ equation) and there is a violation of conservation of energy. Is this a reason?  Also, is there any thing called the relativistic mass of the photon? What uses are there for "placement new"? What lies beyond the Sedenions What is so bad about singletons? What does the Recycle Bin in Windows actually do?  Is it just a glorified folder and a holding place for soon to be deleted files, or does it do something specific?  Specifically, are files that are "moved" to the Recycle Bin actually moved on the hard disc, or are just the pointers to the files moved?  I am a fairly experienced user, I just wanted a more depth explanation of the Recycle Bin. Review audit ignores closereason filter Execute Java from command line I want to run a command when there are only 10 entities left. I know you can use /execute unless entity to detect when all matching mobs have died, but it doesn't work if you want to run a command when there are for example 10 entities left.  A command like /execute if entity @e[limit=10] does not work, it also triggers if there is only one entity.  Such a counting system could also be used to determine once there is only one player left in an arena, meaning they have won a battle or similar. Transforming Differential Equation to a Kummer's Equation I'm trying to transform an equation of the form $$ yw^{\prime\prime}(y) - [b - ay] w^\prime(y) - [d + ey]w(y) = 0 $$ into the form of a Kummer's or confluent hypergeometric differential equation: $$ y w^{\prime\prime}(y) + [f - y] w^\prime(y) + g w(y)  = 0 $$ I know it may have something to do with merging two of the singularities of the original equation, and maybe doing something with $y$, making it $\frac{y}{b}$ and taking b to infinity, but I don't know and can't find the details for this process, and for my equation specifically. There's not too much difference between the two but just enough so that I can't get it. Thanks in advance for any help! I am running a query like   select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d';   on table that looks like                                      Table "public.students"           Column       |            Type             |             Modifiers                   -------------------+-----------------------------+------------------------------------      id                | uuid                        | not null default gen_random_uuid()      school_id        | uuid                        |  Indexes:     "students_pkey" PRIMARY KEY, btree (id)     "students_school_id_idx" btree (school_id)   The query plan for the select statement with just where looks like below-  explain select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d';                                             QUERY PLAN                                             --------------------------------------------------------------------------------------------------  Bitmap Heap Scan on students  (cost=581.83..83357.10 rows=24954 width=16)    Recheck Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)    -&gt;  Bitmap Index Scan on students_school_id_idx  (cost=0.00..575.59 rows=24954 width=0)          Index Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)   This is fairly fast.  Now we add order by to the query with id that degrades the query.(Such a query is generated by Rails like student.first with some condition)  explain select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d' order by id asc limit 1;                                                  QUERY PLAN                                                  ------------------------------------------------------------------------------------------------------------  Limit  (cost=0.43..488.51 rows=1 width=16)    -&gt;  Index Scan using students_pkey on students  (cost=0.43..12179370.22 rows=24954 width=16)          Filter: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)   How can I improve the speed to return the results of this query? Currently there are around 4990731 records in the table and is taking more than 2 minutes! Its running on RDS with db.t2.medium instance.  UPDATE After running Analyze students;  explain select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d' order by id asc limit 1;                                                        QUERY PLAN                                                         -----------------------------------------------------------------------------------------------------------------      Limit  (cost=8.46..8.46 rows=1 width=16)        -&gt;  Sort  (cost=8.46..8.46 rows=1 width=16)              Sort Key: id              -&gt;  Index Scan using students_school_id_idx on students  (cost=0.43..8.45 rows=1 width=16)                    Index Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)      explain analyze select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d' order by id asc limit 1;                                                                           QUERY PLAN                                                                              -----------------------------------------------------------------------------------------------------------------------------------------------------------     Limit  (cost=8.46..8.46 rows=1 width=16) (actual time=1.853..1.855 rows=1 loops=1)      -&gt;  Sort  (cost=8.46..8.46 rows=1 width=16) (actual time=1.851..1.852 rows=1 loops=1)            Sort Key: id            Sort Method: quicksort  Memory: 25kB            -&gt;  Index Scan using students_school_id_idx on students  (cost=0.43..8.45 rows=1 width=16) (actual time=1.841..1.843 rows=1 loops=1)                  Index Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)     Planning time: 0.145 ms     Execution time: 1.874 ms What do damage buffs affect? In Overwatch, there are several ways to buff the damage dealt by a hero: the alternate fire of Mercy's Caduceus Staff, Ana's Nano Boost, and Orisa's Supercharger. Are they all governed by the same rules? What can they affect, or not affect?  This question exists to have a single reference point for the many, many questions that have been asked, instead of having to update each answer individually when game mechanics change Are all algebraic integers with absolute value 1 roots of unity? Fixing scrolling in nano running in tmux in mate-terminal The problem:   I open a terminal (in Linux Mint, so mate-terminal) zsh is the shell Then I run tmux Edit a file with nano Scroll up and down that file with the cursor Issue: When scrolling down in nano, only the bottom half of the terminal window gets refreshed Issue: When scrolling up in nano, only the top half of the terminal windo gets refreshed   The complete nano view of file does not get refreshed in my terminal window when scrolling. Any tips?  Edit: my .tmux.conf  It seems that this line specifically is the culprit (as commenting it out fixes the problem):  set -g default-terminal "xterm-256color"   I'm pretty sure I added that line because I have issues even running nano during an SSH session.  Here is the full file:  set-option -g default-shell /bin/zsh  # Make sure tmux knows we're using 256 colours, for # correct colourised output set -g default-terminal "xterm-256color"  # The following were marked as "unknown", so # I do know what I'm doing wrong. #set -g mode-mouse on #setw -g mouse-select-window on #setw -g mouse-select-pane on  # Attempting to stop "alert" sound upon startup # but none of these are working... set-option bell-on-alert off set-option bell-action none set-option visual-bell off How to install h.264 decoder?