I know that in PHP, the only difference between double quotes and single quotes is the interpretation of variable inside a string and the treatment of escape characters.
In JavaScript, I often see double quotes used in strings. Is there a particular reason for that, or are single quotes exactly the same as double quotes?
You'll want to use single quotes where you want double quotes to appear inside the string (e.g. for html attributes) without having to escape them, or vice versa. Other than that, there is no difference.
However, note that JSON (JavaScript Object Notation) only supports double quoted strings.