RPS.js

// Initializing Variables
var userChoice = prompt("Do you choose rock, paper or scissors?");
var computerChoice = Math.random();

// Validation for user input
//if ( userChoice != "rock" || "paper" || "scissors" ) {
//  userChoice = prompt("You did not select rock, paper, or scissors. Please try again.");
//}

// Randomly selecting correct value for computerChoice
if ( computerChoice < 0.34 ) {
	computerChoice = "rock";
} else if ( computerChoice <= 0.67 ) {
	computerChoice = "paper";
} else {
	computerChoice = "scissors";
}

// Function that compares the two values
function compare( userChoice, computerChoice ) {
	
	if ( userChoice === computerChoice ) {
		return "The result is a tie!";
	}
	
	switch ( userChoice ) {
		case "rock":
			return (computerChoice === "scissors" ? "Rock" : "Paper") + " wins!";
			break;
		case "paper":
			return (computerChoice === "rock" ? "Paper" : "Scissors") + " wins!";
			break;
		case "scissors":
			return (computerChoice === "paper" ? "Scissors" : "Rock") + " wins!";
			break;
	}
	
}


compare(userChoice, computerChoice);