'Mastering JavaScript one line at a time! // #CodingJourney'

"Mastering JavaScript one line at a time! // #CodingJourney"

In JavaScript, you can create a single-line comment using double slashes "//" at the beginning of the line. Anything written after the slashes will be treated as a comment and will not be executed by the JavaScript interpreter.

Here's an example:

```javascript
// This is a single-line comment in JavaScript

var x = 5; // This variable stores the value 5
```

In the above code, the first line is a single-line comment that will be ignored by the interpreter. The second line declares a variable `x` and assigns it the value 5. The comment after the variable assignment is another single-line comment.

Single-line comments are useful for adding explanatory notes or temporarily disabling specific lines of code without deleting them.