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SEARCH KEYWORD -- event delegation



  4 asynchronous programming methods in JavaScript

You may know the execution environment of JavaScript is single threaded. The so called single thread means only one task can be running at any time, if there are many tasks, they need to be in a queue and wait for the previous task to be completed. The advantage of this mode is it's easy to implement and the execution environment is relative simple; the disadvantage is that if one task takes long time, the tasks following it must wait in the queue and this will delay other tasks consequently. Th...

   JAVASCRIPT,ASYNCHRONOUS PROGRAMMING, EVENT MODEL,PROMISE     2012-12-25 00:55:47

  Using JavaScript to operate clipboard

Browsers allow JavaScript to read and write data on clipboard. Generally script should not modify user's clipboard to avoid impacting user expectation, but there are cases where this can indeed bring convenience to users. For example, for some code snippet, user can copy it to clipboard with one click instead of select and copy manually. There are three options for clipboard operation provided in JavaScript/browser: document.execCommand() Asynchronous Clipboard API copy and paste events This p...

   JAVASCRIPT,CLIPBOARD,NAVIGATOR.CLIPBOARD     2021-01-23 23:23:34

  XMLHttpRequest Level 2 user guide

XMLHttpRequest is a web browser interface, it makes it possible for JavaScript doing HTTP(s) communication. Microsoft's IE5 first introduced XMLHttpRequest, because it's so useful that many other browsers also adopted this. AJAX came to the front since. However, this interface is not standardized, implementation among different browsers is different, with the emerging of HTML5, W3C is considering to standardize this interface. In February 2008, they proposed a XMLHttpRequest Level 2 draft. This ...

   XMLHttpRequest, progress, upload, binary data     2012-09-19 11:51:50

  Supervisord, God and Monit, which one to choose?

With the popularity of Docker, more and more service have been moved into docker containers and they are easy to build up and maintain for each atomic service(though it's a bit complex to maintain multiple docker containers which contain different service to form a complete solution). Ideally, each docker container should only contain one service which has only one running process. However, in reality there would be cases multiple processes would run in one single docker container and there is a...

   DEVOPS,MONIT,SUPERVISORD,GOD,DOCKER     2017-11-25 12:28:11

  Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design. Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing? In this article, let's explore why Redis has a single-threaded architecture and still maintains its spe...

   REDIS,SINGLE-THREADED,MULTI-THREADING     2023-02-28 05:16:22

  File upload once again

File upload is one of the oldest operation of web design. After 20 years, it's still has no big change, difficult to handle, lack of interaction and poor user experience. Web developers have thought many methods to improve the experience of uploading file in web apps, they developed various plugins based on different JavaScript libraries. However, because of the difference among different web browsers, there is no common interface which makes these plugins work properly or easily on all web brow...

   Web design, File upload, Asynchronous,HTML5     2012-09-02 11:52:21

  Solution to getKeyCode() returns 0 in Java

The getKeyChar method always returns a valid Unicode character or CHAR_UNDEFINED. Character input is reported by KEY_TYPED events: KEY_PRESSED and KEY_RELEASED events are not necessarily associated with character input. Therefore, the result of the getKeyChar method is guaranteed to be meaningful only for KEY_TYPED events.For key pressed and key released events, the getKeyCode method returns the event's keyCode. For key typed events, the getKeyCode method always returns VK_UNDEFINED....

   Java,KeyCode,0,KeyListener     2011-06-06 10:38:11

  CSS box-shadow Can Slow Down Scrolling

Working on one of the Chromebooks Google lets you borrow on Virgin America flights, I noticed scrolling down the page on my airbnb.com dashboard was much slower than on my normal laptop. I chalked it up to weak Chromebook hardware, but other sites were scrolling just fine. box-shadow had caused slow scrolling on our search results page before, so I did some investigation.I used Chrome's Timeline tab to see the duration of paint events on the page. Before each test I forced a garbage collection a...

   CSS,box-shadow,performance,Timeline,Chromebook     2011-11-13 08:13:48

  That “JavaScript not available” case

During some interesting discussions on Twitter yesterday I found that there is now more than ever a confusion about JavaScript dependence in web applications and web sites. This is a never ending story but it seems to me to flare up ever time our browsing technology leaps forward. I encountered this for the first time back in the days of DHTML. We pushed browsers to their limits with our lovely animated menus and 3D logos (something we of course learned not to do again, right?) and we were ...

   JavaScript,Security,Banned,Reason     2012-01-04 02:37:35

  Modal dialog in Java example code

In Java, we can create modal dialog so that the main JFrame cannot be operated on until the modal dialog is closed. To achieve this, we need to use one class in Java--JDialog. This class can be used to create an modal dialog.Example code : import javax.swing.JDialog; import javax.swing.JLabel; import javax.swing.JPanel; public class Dialog extends JDialog{ public Dialog(){ super(); JPanel panel=new JPanel(); panel.add(new JLabel("Hello dialog")); this.getCont...

   Java,Modal,JFrame,JDialog,Demo,Code     2011-08-18 09:50:27