Why 2 /// 2 - 2 in Javascript?

Question

Does anyone know why 2 /// 2 is 2 in Javascript?

What is this behavior called? Is this documented somewhere? Thanks.

Answer 1

The answer is simple: a one-line comment. The first two slashes start the comment, so the whole operator is just 2

Answer 2

It is called a comment. Everything that starts with // is a comment on one line.

Your code is essentially 2 , since the rest of the line is the comment " / 2 ".

Answer 3

// enter a single line comment in JavaScript

Answer 4

This is called a comment:

 2 /// 2 

It is equal to:

 2 

Because everything after and including // ignored (to the next line). JavaScript also has this awful feature in which it automatically inserts semicolons before newlines so that the code does not interrupt when you do something like this:

 var x = 2 /// 2 

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BTW: Use a text editor with syntax highlighting.