[Solved] What does /[[${}]]/ means in JavaScript?

Question

▶ 1^st Question:

Everything inside /* */ is considered a comment in JavaScript, PHP, CSS and most likely more languages that I’m not aware of.

There are some programs, however, that use the content inside comments, if it’s appropriate, to turn on/off settings, such as JSLint and even Stack Overflow’s snippets.

▶ 2^nd Question:

Instead of declaring variables like:

var a = 0;
var b = 3;
var c = 8;
var d = 17;

You can separate them by comma, thus using a single var keyword:

var a = 0,
    b = 3,
    c = 8,
    d = 17;

▶ 3^rd Question:

Both the code and message variables contain the empty string.

code= "";
message = "";

▶ 4^th Question:

The alert works as usual without, though, showing any message.

Accepted Answer