var person = ["Sam", "John", "Mary", "Liz"];

​

​

var firstName = prompt("enter name");

​

var message;

​

for (var x in person) {

//   var firstName = person[x];

  if (firstName == person[x])

    {

      message = "Found Person";

      break;

    }

  else 

    {

      message = "Not Found";

      break;

    }

  //console.log(firstName);

}

​

console.log(message);