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  Best practices of front end optimization

1. Use DocumentFragment or innerHTML to replace complex elements insertion DOM operation on browser is expensive. Although browser performance is improved much, multiple DOM elements insertion is still expensive and will affect the page load speed. Assume we have an ul element on our page, we now want to retrieve a JSON list using AJAX and then update the ul using JavaScript. Usually we may write it as : var list = document.querySelector('ul'); ajaxResult.items.forEach(function(item) { // ...

   JavaScript,Front end,Optimization,Tips     2013-07-06 11:26:27

  Can a === 1 && a === 2 && a === 3 be true in JavaScript?

Lots of you may be aware that there is famous interview question which asks whether a == 1 && a == 2 && a == 3 can be true in JavaScript. And the answer to this question is YES. The reason is that == will do a non-strict comparison which will evaluate a to a number and this provides the possibility of dynamically return the value when every time a is accessed. Have you ever wondered whether a === 1 && a === 2 && a === 3 can be true? At first glance, it seems this ...

   JAVASCRIPT,===,STRICT COMPARISON     2018-04-06 12:17:29

  Set PHP session timeout

There are many different discussions about PHP sessions. We may often face some weird issues while handling PHP sessions. Sometimes session is expired earlier than expected. Or sometimes the session is not expired. This introduces many confusions. Today we discuss how to set PHP session timeout correctly today. In php.ini, there are three key parameters which will affect the session timeout. session.gc_maxlifetime, session.gc_probability and session.gc_divisor. session.gc_maxlifetime defined the...

   PHP,session,timeout     2013-08-31 08:11:03

  Convert time to Unix time

Unix time is defined as the number of seconds that have elapsed since midnight Coordinated Universal Time (UTC), 1 January 1970,not counting leap seconds. It is used widely in Unix-like and many other operating systems and file formats. It is neither a linear representation of time nor a true representation of UTC. Unix time may be checked on some Unix systems by typing date +%s on the command line. Sometimes it's a bit difficult to compare times stored in different applications or systems with ...

   UNIX time, Oracle DATE, conversion, timestamp     2013-01-19 09:04:17

  Replacing small C programs with Haskell

C is the classic go-to tool for small programs that need to be really fast. When scripts.mit.edu needed a small program to be a glorified cat that also added useful HTTP headers to the beginning of its output, there was no question about it: it would be written in C, and it would be fast; the speed of our static content serving depended on it! (The grotty technical details: our webserver is based off of a networked filesystem, and we wanted to avoid giving Apache too many credentials in ca...

   C,Haskell,Small program     2012-01-03 10:51:39

  Ruby net-scp cannot scp multiple files with asterisk(*)

net-ssh/net-scp is a Ruby gem which can be used to scp files between different *nix machines. It's similar to how the *nix scp command. It can be used to scp a file or a directory. However, it seems it has some problem to scp multiple files using pattern *. For example, below script is supposed to download all files from remote directory to local directory: require 'net/scp' host = 'testmachine' login = 'testaccount' password = "testpassword" remote_path = '/tmp/remote...

   NET-SCP,RUBY,ASTERISK,MULTIPLE FILES     2016-10-20 03:00:13

  Our Go Cache Library Choices

In Build a Go KV Cache from Scratch in 20 minutes, I walked you through what matters when writing a local cache, and eventually implemented one, whose performance was beaten badly by that of the popular go-cache on Github though. However, the bright side is that we can learn a lot from those excellent Github Go cache products, studying their features, applicable scenarios, and implementations, and extracting what we need. In this article, I will mainly analyze and compare the four...

   GOLANG,CACHE,GO-CACHE,BIGCACHE,GOURPCACHE     2022-04-16 07:48:11

  Understanding database, instance and schema in Oracle database

Oracle database is the most popular database system among enterprises. To start working on Oracle database, some concepts must be understood first. They include database, instance, schema and user etc. And among these concepts, some have different meanings from those in other database systems such as MS SQL, MySQL, DB2. On the web, there are already some good posts which explain different concepts such as Ask Tom's database vs instances, Difference between database vs user vs schema. In this pos...

   DIFFERENCE,DATABASE,ORACLE DATABASE,INSTANCE,SCHEMA,USER     2016-12-14 23:30:56

  Automatically Updating Charts for Additional Data in Excel

Excel shines at turning your data into charts—graphical representations of your data. You can easily create a chart based on a range of data in a worksheet. Normally, if you add additional data to your range, you will need to once again create the chart or at best change the range of cells on which the chart is based. If you get tired of modifying charts to refer to new data ranges, there are a couple of shortcuts you can try out. The first shortcut works fine if you simply need to...

   Excel,Graph,Auto update,New data,Automat     2011-08-13 04:36:53

  PHP to integrate with Sign in with Google

Google has a huge user base and hence it provides an authentication service for third party service to integrate with them so that people can sign in with Google in their services. Google also adopts OAuth 2 to provide this kind of Open ID connect service. This post will introduce how to integrate with sign in with Google functionality in your PHP website.  Create a client app on Google The first step you should follow is to create a Google app, you can follow the post here to create the p...

   PHP,GOOGLE API,OPEN API,SIGN IN WITH GOOGLE     2019-03-03 02:00:09