File size validation in javascript / jQuery?
Get file size before uploading
A coin is tossed three times: The probability of zero heads is 1/8 and the probability of zero tails is 1/8.  And my question is: What is the probability that all three tosses result in the same outcome?   So, if P(zero heads)= 1/8 , then that should be the same of p(all tails)?  If so, we could use the Addition Rule which is $P(A \cup B) = P(A) + P(B)$  where A and B are disjoint events, i.e. $A \cap B = \emptyset$, A is the event of tossing all heads and B is the event of tossing all tails.  I'm not sure how to continue after that... would the complement be used? For what powers $k$ is the polynomial $n^k-1$ divisible by $(n-1)^2$? Want to switch from software development to testing domain Step in the Stein's proof of Plancherel Theorem What's the difference between a microcontroller and a microprocessor? How to fully backup non-rooted devices? I know I'm asking for the close-to-impossible -- as a real full-backup certainly requires root permissions. But still there are many folks around not wanting to root their devices -- afraid of voiding their warranties or bricking their devices, or just not having their devices supported by any rooting method.  I also know there were a lot of questions asked already on this topic, and I checked all of them having the backup tag -- none covers the entire topic, all just have pieces, and especially people new to Android (but other non-power-users as well) would have a hard time figuring out the best way.  So I want a detailed canonical answer to the question:  Not involving root-solutions, how to achieve a backup as close as possible to a full backup?  Please do not give simple one-liner answers like "Use app xyz [full-stop]." If mentioning an app (and I doubt a single app would be the answer here), include what parts are covered by it -- as well as ideas on how to fill the gaps it leaves. (And to make it absolutely clear: I know the first thing coming to mind is Titanium Backup -- I use it myself, but this does not apply here: This question is strictly about methods for non-rooted devices!) Moreover, the answer should be as generic as possible in terms of applying to a wide range of devices (i.e. it should not be restricted to one device or manufacturer).  I already mentioned having investigated all questions here tagged backup. These will certainly be helpful providing details for answers here, so I will list up the topmost ones concerning my question:            All these provide some details for my question (so feel free to get inspired by them) -- but I feel there are still details missing. Also it would be helpful to have a summary -- say, an answer including the full description of "the maximum possible".  A last criterium: While I'd consider cloud-based solutions legit, I'd favour local solutions. If you can provide both: all the better. But some people value privacy quite high (I'm one of them), and thus would not trust their data to some cloud service.    Thanks to Ryan, we now have a solution for a really complete backup of all apps and their data -- which I didn't dare to hope for! The only disadvantage: His solution only works for less than 10% of all Android users; namely those whose devices are running at least with Android 4.x.  So again, I ask the close-to-impossible: Any solutions applicable at least on Gingerbread (2.3.x) or, better, even Froyo (2.2.x) -- so they cover the majority of current devices? These solutions may involve multiple tools (try to keep it as simple as possible though; think of your mother to follow your instructions ;)  And keep in mind: NO ROOT!    To further motivate high-quality answers (and hopefully avoid low-quality ones), I will be a harsh one here: As I rarely do, I will down-vote answers not fitting the mentioned criteria on one end -- but on the other end, I will setup a bounty for the best answer (which cannot be done immediately, but earliest after 2 days). `sudo echo "bla" >> /etc/sysctl.conf` permission denied Disclaimer: I'm pretty novice at sysadmin stuff.  I'm trying to set up port forwarding in an AWS EC2 instance, this has to be done in the command-line because I don't want to go in and edit anything, it has to be automatic (it's part of a build process).   sudo echo "net.ipv4.ip_forward = 1" &gt;&gt; /etc/sysctl.conf      Permission denied   The weird thing is I've been (successfully) using sudo for pretty much every command that required su privileges. If I do sudo su before the command (trying it out by hand in an ssh session), then it works.  Reasons behind this? Possible solutions that don't involve sudo su or manual edits? Uploading video to youtube in right format I have a Sony CX115 and I have a little footage I'd like to put on youtube. I've downloaded Arista from the Ubuntu Software Center and then I've downloaded its Youtube HD plugin. I've converted my video and uploaded it to youtube... The result is a flashy video with a lot of grey in it:    What could I do to publish it in high quality so it'll be viewable? I need to create file with name is the result of the command in Solaris I need to create only one file with name is the result of the command ls -l | head -2. I can't use environment variables. The filename must contain newline symbols.  I've tried to use touch 'ls -l | head -2', but it hasn't worked. How to get full query text from performance_schema.threads? According to : Access to the threads table does not require a mutex  and has minimal impact on server  performance. The other sources have negative performance consequences because they require a mutex.   So yes, I want to use threads table to examine running queries. The trouble is, the PROCESSLIST_INFO column does not contain the full query. It just contains a truncated version of the query. There is a flag viz performance_schema_max_sql_text_length which controls how many bytes are allocated for the SQL query. But it seems to affect the events_statements_history_long table. There is no change in the thread table output. There is also the events_statement_current table. But it is not clear if accessing that table affects performance or not. Best way to reverse a string I've just had to write a string reverse function in C# 2.0 (i.e. LINQ not available) and came up with this:  public string Reverse(string text) {     char[] cArray = text.ToCharArray();     string reverse = String.Empty;     for (int i = cArray.Length - 1; i &gt; -1; i--)     {         reverse += cArray[i];     }     return reverse; }   Personally I'm not crazy about the function and am convinced that there's a better way to do it. Is there? Let $(e_n)$ (where $ e_n $ has a 1 in the $n$-th place and zeros otherwise) be unit  standard vectors of $\ell_\infty$.   Why is $(e_n)$ not a basis for $\ell_\infty$?  Thanks. What is the status of TTF support in Internet Explorer? Who was the piano player that Starbuck met in the bar on Galactica? Towards the end of season four, Starbuck meets a piano player in the makeshift bar on Galactica.  Now, it appears that this guy is some kind of ghost/angel like Caprica-6 and the ghost Baltar - but I have an idea that he could also be the original copy of the seventh model (Daniel). It's mentioned right in the episode before that Cavil poisoned all of the bodies that were being prepared to accept a copy of Daniel - but it's ambiguous about the fate of the original cylon with that personality. Daniel was also mentioned as an 'artist' and 'sensitive' person.  So - could it have been Daniel that helped Starbuck realise what the music meant? The cast to value type 'Int32' failed because the materialized value is null So I'm making this summary of a course where I've only been getting information from one book. Sometimes I want to show what page from the book a statement is taken from but I can't figure out a clean way of doing it.  Basically I would like to have something (in function) similar to:  "Statement[Book p123]"  Do you have any suggestions? Where can I find computer modern fonts for use in other programs, e.g. Adobe Illustrator? How to change specific values in a List Using a web service is often an excellent architectural approach. And, with the advent of WCF in .Net, it's getting even better.  But, in my experience, some people seem to think that web services should always be used in the data access layer for calls to the database. I don't think that web services are the universal solution.  I am thinking of smaller intranet applications with a few dozen users. The web app and its web service are deployed to one web server, not a web farm. There isn't going to be another web app in the future that can use this particular web service. It seems to me that the cost of calling the web service unnecessarily increases the burden on the web server. There is a performance hit to inter-process calls. Maintaining and debugging the code for the web app and the web service is more complicated. So is deployment. I just don't see the advantages of using a web service here.  One could test this by creating two versions of the web app, with and without the web service, and do stress testing, but I haven't done it.  Do you have an opinion on using web services for small-scale web app's? Any other occasions when web services are not a good architectural choice? What are: province, territory, protectorate, state...? Often a country will have regions called "provinces" or "states". Other times they are called "territories" and "protectorates".   Is there a generic term for these words?  Is there a full list of words that belong to this group?  What makes them different from each other?