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javascript - How do I find out which DOM element has the focus?

I would like to find out, in JavaScript, which element currently has focus. I've been looking through the ... the focus over in the event handling functions. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Scala 2.8 breakOut

In Scala 2.8, there is an object in scala.collection.package.scala: def breakOut[From, T, To](implicit b : ... breakOut being called as an argument to my List? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - Can I make a <button> not submit a form?

I've got a form, with 2 buttons <a href="index.html"><button>Cancel changes</button></a> <button type=" ... it didn't work as expected (looked quite ugly!). Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - "Uncaught SyntaxError: Cannot use import statement outside a module" when importing ECMAScript 6

I'm using ArcGIS JSAPI 4.12 and wish to use Spatial Illusions to draw military symbols on a map. When I add milsymbol. ... "; ms.Symbol = Symbol; export { ms }; Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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How do you find all subclasses of a given class in Java?

How does one go about and try to find all subclasses of a given class (or all implementors of a given ... How does one go about and do it programmatically? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - Assign click handlers in for loop

I'm having several div's #mydiv1, #mydiv2, #mydiv3, ... and want to assign click handlers to them: $(document). ... 'you clicked 20'. What am I doing wrong? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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What is the purpose of the expression "new String(...)" in Java?

While looking at online code samples, I have sometimes come across an assignment of a String constant to a ... would anything even be allocated on the heap? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why doesn't polymorphism work without pointers/references?

I did find some questions already on SO with similar title- but when I read the answers they were focussing ... this would have been enough- obviously not. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Why is volatile used in double checked locking

From Head First design patterns book, the singleton pattern with double checked locking has been implemented as ... double checked locking i.e performance? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Can you split/explode a field in a MySQL query?

I have to create a report on some student completions. The students each belong to one client. Here are the tables ( ... c.`courseNames`)[e.`courseId`] FROM ... Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Loading and displaying large text files

In a Swing application, I sometimes need to support read-only access to large, line-oriented text files that are ... in the 10-100 megabyte, million-line range? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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JavaScript plus sign in front of function expression

I've been looking for information about immediately invoked functions, and somewhere I stumbled on this notation: + ... in front of the function means/does? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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How do I display an alert dialog on Android?

I want to display a dialog/popup window with a message to the user that shows "Are you sure you want to ... I invoke a dialog or popup and its functionality? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - XDocument or XmlDocument

I am now learning XmlDocument but I've just ran into XDocument and when I try to search the difference or benefits ... me why you would use one over another ? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mongodb - Find document with array that contains a specific value

If I have this schema... person = { name : String, favoriteFoods : Array } ... where the favoriteFoods ... I was expecting to find before knowing the solution) Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - How to run Conda?

I installed Anaconda and can run Python, so I assume that I installed it correctly. Following this introductory ... I am working on a Linux system. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference

When my SplashActivity opens the LoginActivity my app crashes. The following is my SplashActivity.java: package ... .os.ZygoteInit.main(ZygoteInit.java:1199) Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - Is floating point arbitrary precision available?

Just for fun and because it was really easy, I've written a short program to generate Grafting numbers, but because ... to move to C and use GMP or something? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Something seems wrong with the layout, JButton showing unexpected behaviour at resize of the window

JRE Version 1.7 Update 3 EXPECTED BEHAVIOUR As I run the program, it works as expected, everything works smoothly. As ... ballDiameter); } } **LATEST EDIT : ** Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - How can I generate random alphanumeric strings?

How can I generate a random 8 character alphanumeric string in C#? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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257 views

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Targeting only Firefox with CSS

Using conditional comments it is easy to target Internet Explorer with browser-specific CSS rules: <!--[if IE ... conditional comments are only 'special' to IE Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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http headers - How do I force files to open in the browser instead of downloading (PDF)?

Is there a way to force PDF files to open in the browser when the option "Display PDF in browser" is unchecked? ... when that option is checked. What can I do? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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scope - Scoping in Python 'for' loops

I'm not asking about Python's scoping rules; I understand generally how scoping works in Python for loops. ... be caught by interpreters in other languages. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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193 views

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database design - Calculating and saving space in PostgreSQL

I have a table in pg like so: CREATE TABLE t ( a BIGSERIAL NOT NULL, -- 8 b b SMALLINT, -- 2 b c ... option? Would there be a speed penalty? Any other ideas? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - MySQL: Alternatives to ORDER BY RAND()

I've read about a few alternatives to MySQL's ORDER BY RAND() function, but most of the alternatives apply only to ... OR u.stamp=1) ORDER BY RAND() LIMIT 18 Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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295 views

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excel - How can I find last row that contains data in a specific column?

How can I find the last row that contains data in a specific column and on a specific sheet? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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366 views

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caching - How can I force clients to refresh JavaScript files?

We are currently working in a private beta and so are still in the process of making fairly rapid changes, ... you using a process that simplifies the change? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Android Endless List

How can I create a list where when you reach the end of the list I am notified so I can load more items? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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