&lt;tfoot&gt;     &lt;select&gt;         &lt;option value="222"&gt;&lt;/option&gt;         &lt;option value="2222"&gt;2222&lt;/option&gt;         &lt;option value="zaza"&gt;zaza&lt;/option&gt;     &lt;/select&gt; &lt;/tfoot&gt;   I tried that:   $('tfoot select').val('zaza');     $("tfoot select").val("zaza") &lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"&gt;&lt;/script&gt;  &lt;tfoot&gt;     &lt;select&gt;         &lt;option value="222"&gt;&lt;/option&gt;         &lt;option value="2222"&gt;2222&lt;/option&gt;         &lt;option value="zaza"&gt;zaza&lt;/option&gt;     &lt;/select&gt; &lt;/tfoot&gt;     Any idea ?  Select = make it selected = trigger the change event
If you know the Index, Value or Text. also if you don't have an ID for a direct reference.  ,  and  are all helpful answers.  Example markup  &lt;div class="selDiv"&gt;   &lt;select class="opts"&gt;     &lt;option selected value="DEFAULT"&gt;Default&lt;/option&gt;     &lt;option value="SEL1"&gt;Selection 1&lt;/option&gt;     &lt;option value="SEL2"&gt;Selection 2&lt;/option&gt;   &lt;/select&gt; &lt;/div&gt;
Quoted headings are rendered properly on preview but not when posted With markdown, you can use some dashes for headings. For example, this: Hello ---- this is some other text  renders as this: Hello this is some other text This is fine and works well. When I want to quote that text is when the problem arises, since this Markdown: &gt; Hello &gt; ---- &gt; this is some other text  When written down shows well in the preview but not when posted:  Hello this is some other text   As an example, see an screenshot of the preview:    and a screenshot of the posted content, where the ---- becomes a &lt;hr&gt;:  Note a similar bug I also reported: . How many String objects will be created when using a plus sign? How to install Gnome 3 without breaking Unity? I tried installing gnome 3 , but it broke Unity and I had to reinstall Natty from scratch.  Does anyone know if there is a way to install Gnome 3 without breaking Unity? What is the difference between linear regression and logistic regression? What is the difference between linear regression and logistic regression?  When would you use each? What is this style of text-as-image called? I'm seeing a trend (especially on pinterest) of these posters where the image and subject is the text. THe text itself isn't really that important either, it's mainly the typefaces used and composition.  Does this style have a name to it? Is it just called text-as-image? What are the differences between 32-bit and 64-bit, and which should I choose? What is the difference between 32-bit and 64-bit Ubuntu? I've heard the 64-bit platform performs better and can detect more than 4GB of RAM. Also, while some apps haven't ported to 64-bit yet, ia32-libs lets a 64-bit machine run them.  If so, why not promote 64-bit over 32-bit? How to derive variance-covariance matrix of coefficients in linear regression I am reading a book on linear regression and have some trouble understanding the variance-covariance matrix of $\mathbf{b}$:    The diagonal items are easy enough, but the off-diagonal ones are a bit more difficult, what puzzles me is that  $$ \sigma(b_0, b_1) = E(b_0 b_1) - E(b_0)E(b_1) = E(b_0 b_1) - \beta_0 \beta_1 $$  but there is no trace of $\beta_0$ and $\beta_1$ here. Check out the screenshot below, I want to extend my C partition (where Windows is installed) into the unallocated free space shown. This space was cleared up by shrinking the D partition. I can extend the D partition if I want to, but not the C.  Why not? VARCHAR size limit in Excel spreadsheets Should I always use a comma after "e.g." or "i.e."? It seems that a List object cannot be stored in a List variable in C#, and can't even be explicitly cast that way.  List&lt;string&gt; sl = new List&lt;string&gt;(); List&lt;object&gt; ol; ol = sl;   results in Cannot implicitly convert type System.Collections.Generic.List&lt;string&gt; to System.Collections.Generic.List&lt;object&gt;  And then...  List&lt;string&gt; sl = new List&lt;string&gt;(); List&lt;object&gt; ol; ol = (List&lt;object&gt;)sl;   results in Cannot convert type System.Collections.Generic.List&lt;string&gt; to System.Collections.Generic.List&lt;object&gt;  Of course, you can do it by pulling everything out of the string list and putting it back in one at a time, but it is a rather convoluted solution. Is there a single word for “one who explains his point of view very clearly”? Why isn’t singular ‘they’ used with 3Sg verb forms? There are many (duplicate) questions about the acceptance, popularity and history of singular they (and their, them and themself) around here, it even got a tag of its own. If I didn’t miss anything, however, the proper verb form hasn’t been questioned yet.  As we all know, English third person singular pronouns (it, she, he and one, +body), names (Alice, Bob, …) and nouns (student, teacher, …) demand the +(e)s suffix be added to the finite verb form in simple present, where some auxiliary verbs have a “special” form (is &lt; *bes / *ares and has &lt; *haves). All other subjects don’t, including plural third person pronoun they.  When the plural you replaced thou (with thee, thy / thine), the other marked verb form that had remained in English – i.e. suffix +(e)st or +t – vanished, too. The first and second persons only ever appear as pronouns (I, we; you), not names or nouns, so there was no strong inclination to keep the verbal inflection.  The second person precedent would suggest that singular they be used with uninflected verb forms which is how it’s usually encountered in the wild. Assuming that they someday replaces he and she (and maybe it) it would lead to disagreement with the words the pronoun stands in for:        Alice         goes to her   place  by herself.   Bob           goes to his   place  by himself.   Alice and Bob go   to their place  by themselves. – (common)   Alice and Bob go   to their places by themselves. – (separate)                  She  goes to her   place  by herself.   He   goes to his   place  by himself.   They go   to their place  by themselves.   They go   to their places by themselves.                  They ?goes to their place  by themself.   ditto   They  go   to their place  by themselves.   They  go   to their places by themselves.                  They ?go to their place  by ?themselves.   ditto   They  go to their place  by  themselves.   They  go to their places by  themselves.      So why doesn’t singular they afford s on present-tense verbs like all other third person singular subjects do?   I learned about singular they only long after I had been taught English as a second language in school. That’s why it’s still a conscious decision to use it and hence I could easily adapt to use s forms with it, but would that sound and look funny / strange / wrong to native speakers? Can virtual particles be thought of as off-shell Fourier components of a field? I just found  blog post, which gives an interpretation of virtual particles I haven't seen before.  Consider a 1D system of springs and masses, where the springs are slightly nonlinear. A "real particle" is a regular $\cos(kx-\omega t)$ wavepacket moving through the line, where $\omega$ satisfies the dispersion relation $\omega = \omega(k)$. When two real particles collide, the region where they collide temporarily looks really weird, as they interact nonlinearly, pulling and pushing on each other.  Formally, we can write this weird region as the sum of a bunch of $\cos(kx-\omega t)$ waves, but there's no guarantee they'll have the right dispersion relation. Thus, each term in the resulting expansion is a off-shell "virtual particle". If you add up all the virtual particles, you get the actual intermediate field state, which is just a weird ripple in the field where the two particles are interacting.  As another example, consider the statement "a static EM field is made of virtual particles". Under this interpretation, what that really means is, "a static field (e.g. $1/r^2$) is not equal to $\cos(kx-\omega t)$, but may be expanded in terms of such sinusoids", which is much less mysterious sounding. In fact, this is exactly what we do when we consider scattering off a potential in normal QM, e.g. in the Born approximation.  The above gives some intuition for what a 'virtual particle' means in classical field theory. They are the Fourier components of the field with $(\omega, k)$ not satisfying the dispersion relation, and they are useful in classical perturbation theory. However, they are not propagating degrees of freedom, so they only appear during interactions.   The picture above is entirely classical. Does this picture generalize to quantum field theory, giving a physical intuition for virtual particles there? Why do proof authors use natural language sentences to write proofs? I haven't read very many proofs. The majority of the ones that I've read, I've read in my first-year proofs textbook. Nevertheless, its first chapter expatiates on the proper use of English in mathematical proofs, so I suspect that most proof authors do use both English (or another natural language) and formal proof systems for writing their proofs. However, I can't imagine many circumstances where mathematical notation and a formal proof system wouldn't suffice to convey the author's pertinent thoughts.   I suspect that proof authors have good reasons for making use of both English and formal expressions in their proofs, but I can't think of what those reasons are. Why do proof authors use English and formal expressions to write proofs? Are there stylistic rules (or guidelines) that state how, and in what parts of the proof, an author should, and shouldn't, use English? Other explanation for cosmological redshift? The selection toggle arrows in the Outliner disappeared. Is there some preference in the settings that has to be turned on? When using \textsc, LaTeX issues warning: Font shape `OT1/cmr/bx/sc' undefined Valid characters in a Java class name What characters are valid in a Java class name? What other rules govern Java class names (for instance, Java class names cannot begin with a number)? I've been building my own emacs because I want to fix some issues in it and get the bug fixes upstream. However, Ubuntu keeps automatically removing my own built emacs and I have to keep rebuilding and reinstalling it.  Here's my output of apt-cache policy emacs when I went to bed last night:  ~/emacs$ sudo apt-cache policy emacs emacs:   Installed: 26.0.50.aaron-1   Candidate: 46.1   Version table:      46.1 500         500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages         500 http://us.archive.ubuntu.com/ubuntu xenial/main i386 Packages  *** 26.0.50.aaron-1 100         100 /var/lib/dpkg/status   Here it is when I wake up:  ~/emacs$ sudo apt-cache policy emacs [sudo] password for excelsiora: emacs:   Installed: 46.1   Candidate: 46.1   Version table:  *** 46.1 500         500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages         500 http://us.archive.ubuntu.com/ubuntu xenial/main i386 Packages         100 /var/lib/dpkg/status   Why is this package being versioned at 46 instead of 24 or 25? 26 is the currently the highest major emacs version you can get.   I can see that this is a meta-package:   Why is Ubuntu updating software without asking?  Main Question: What am I supposed to do - assign my package version a number higher than 46 just to make it stick?   That seems like a horrible hack, or maybe that's how it's supposed to work?