General

• Formatting Code in Forums

• An illustrated analogy for explaining dereferencing and value assignment

JavaScript

• A Guide to Semicolons in JavaScript

• Do you need an empty pair of parentheses for a function?

• Object Literals vs. Constructor Notation

• String objects vs. string literals

• var name=function(){} vs. function name(){}

  This question has been asked many times and discussed in great detail in the forums. Please read the answers to these questions:

  • Different formats for defining a function?
  • Why do we use this specific syntax for defining functions?
  • Why do we create functions as variables?

• The new keyword

  Read the OOP section of the JavaScript Glossary on Codecademy. The use of the new keyword is explained under "Class Instances and Usage".

  For more details, read this answer on StackOverflow or this definition in the Mozilla wiki.

• What’s the return keyword?

• Variable scope: local vs. global variables

• Difference between x++ and x = x++

• FizzBuzz – A Simple Solution

• Rock Paper Scissors Lizard Spock

• Inheritance and private variables

• Dynamic variable names

• Addressing Frustration about Badly Written SCTs

• JSLint warning: mixed spaces and tabs

• Chained comparison statement: a < b < c

  JavaScript translates a < b < c to (a < b) < c. The first parentheses will yield true if and only if a is less than b, but then true is compared to c. In that situation, true evaluates to 1, so if c is larger than 1, the whole thing returns true, but this, of course, doesn't mean that b was actually between a and c.

Web

• Classes vs. IDs: See this answer. For more details, read this excellent CSSTricks article.

• CSSLint warning: don’t use IDs in selectors

• Bold, Italic, Emphasis: <b>, <i> vs. <em>, <strong>: read my answer and mtf’s answer.

• Vertical (and horizontal) alignment of text (in circles)

• floated p inside a hyperlink: no underline

Ruby

• Rounding errors and BigDecimal

• Ruby and, or vs. &&, ||

• Ruby Symbol-to-Proc conversion

• Ruby 'single-quoted' vs. "double-quoted" strings

• Sorting with a block: answered in detail here and here

• Value Assignment and x += 1 – with pictures!. This answer isn’t Ruby-specific. It applies to pretty much every programming language.

• Ruby: Counting (down) in steps

• downto doesn’t work with Strings

• Conditional Assignment: x||=y is a shorthand for x=x||y

Python

• return in Python

• Printing Unicode characters in Python 2

• Python string formatting with the % syntax

• 'a' or 'e' or 'i' (or with strings instead of Booleans)

• Python print without inserting a newline

• purify doesn’t work on list [4,5,5,4]: answered here, here, and here.

jQuery

• Avoiding Redundancy in jQuery

• Changing box size on mouseover using jQuery vs. CSS3