JavaScript interview questions

This post will cover the JavaScript questions I have encountered and have seen during my programming career. They will mainly focus on vanilla JavaScript though there are lots of excellent frameworks out there and many people are using them in their daily work. this keyword this keyword is an very important but easy to confuse concept in JavaScript since it is always referring to the calling object of the function. 1. What will be the output of below code snippet? function User(name) { this....

   JAVASCRIPT,ALGORITHM,THIS,CLOSURE     2019-03-09 07:05:46

  What are the Four Most Important Technologies Inside an Office, Today?

The office life has changed a lot since the beginning of the 21st century. Nowadays, technologies have taken over a large part of the work that people have to do, inside their walls. Some of them are more important than others, though. Here are four that no company should live without.  A VoIP Phone System If a company wants to communicate with its clients, it needs to install a centralized phone system. The old ones were complicated and costly. The more phone lines you had, the higher the ...

   SMARTPHONE,VOIP,5G     2022-12-24 06:35:02

  Is programmer really profession for youth only?

- dedicated to the new programmers just into the workplace.

One young Chinese friend asked me: is programmer meant only for less experienced youth? Should I consider transition once if I work on it until 30 years old?

   Programmer,Youth,Product,Project,Career,Analysis     2012-03-18 07:06:44

  Some tricks on PHP session

1. Session timeout problem There is a nuance we found with session timing out although the user is still active in the session.  The problem has to do with never modifying the session variable. The GC will clear the session data files based on their last modification time.  Thus if you never modify the session, you simply read from it, then the GC will eventually clean up. To prevent this you need to ensure that your session is modified within the GC delete time.  You can accomp...

   PHP,Session,Timeout,Solution,Various domain     2015-03-13 07:05:37

  Python object creation sequence

[The Python version described in this article is 3.x] This article aims to explore the process of creating new objects in Python. As I explained in a previous article, object creation is just a special case of calling a callable. Consider this Python code: class Joe: pass j = Joe() What happens when j = Joe() is executed? Python sees it as a call to the callable Joe, and routes it to the internal function PyObject_Call, with Joe passed as the first argument. PyObject_Call looks at the ty...

   Python,Object creation     2012-04-16 15:03:55

  OpenLDAP Proxy -- slapd.conf

In the introductory post of OpenLDAP proxy, we mentioned that slapd.conf is the configuration file which tells the slapd service what to do.  Apart from this, there is a dynamic way of configuring slapd where the configurations are stored in LDIF database. In the future, LDIF database will be the one for configuring slapd, the old style of slapd.conf is deprecated. The slapd.conf can be converted to LDIF style using the slapdtest command. slapdtest -f /etc/ldap/slapd.conf -F /etc...

   OPENLDAP,OPENLDAP PROXY,SLAPD,SLAPD.CONF     2017-10-29 04:01:39

  <=> operator in MySQL

Have you ever seen "<=>" in a SQL query while using MySQL? Does it mean less and equals to and greater than? Actually if you consider it as the union of <= and =>, great, you are close to it. This is one form of equal operator in MySQL, it has the similar meaning to the = operator with some subtle difference. According to MySQL documentation, <=> is NULL-safe equal. This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operand...

   MySQL,NULL safe,<=>     2014-03-24 06:23:22

  3 preconditions for Facebook to enter China

It's well known that Mark Zuckerberg has a big interest in the Chinese market. Recently, the founder of Facebook visited China to attend a development forum held by the Chinese government. Along with the trip, he also paid a trip to some famous places in Beijing such as The Great Wall. He even did a morning run in front of the Tian'an men Square, the symbol of China.  In past few years, Zuckerberg also learned Chinese and read Chinese books, showed his love to the Chinese culture....

   FACEBOOK,CHINA,MARK ZUCKERBERG     2016-03-25 01:32:51

  Open Letter to sites with annoying interfaces

Remember those childhood games where you are given two nearly identical images and your objective was to find some number of subtle differences? Well, I shouldn't have to play that game when I'm using your damn website. I show here two examples of a common practice that is plaguing the modern web. First, a clipping from a project page on github.com.     And now the second image:     See the difference? My question is this: why? That edit button is the only component of...

   Web design,User interface,User friendly,Layout     2011-12-27 09:32:10

  Qualities of a great business presentation

When it comes to business, every day in the industry is spent trying to convince someone into buying your brand, your product or services, no doubt you will find yourself making a lot of pitches and presentations for new products, partners and stakeholders among other things. Having great presentation skills is essential to running a successful business and getting as many people believing in your brand as possible. Great presentations have the following qualities Killer slides PowerPoint slides...

       2015-12-03 23:58:41