Why does the program show error on #pragma strict?

I am new to both Unity and JavaScript.
I went on Youtube for tutorial and followed the steps, but my program just won’t work.

When I entered :

#pragma strict

var moveUp : KeyCode;
var moveDown : KeyCode;

var speed : float = 10;

The program cannot compile and I don’t know why
The error says # is an invalid character and Expected ; at strict
It also requires me to change all the : to ; (semicolon)

Would you be trying to create a C# script, perhaps?