How to use "double quote" inside the string in javascript?

Html page:

<p id="P9"></p>

Javascript page:

<script>

    var x = 'It\'s alright';

    var y = "We are the so-called \"Vikings\" from the north.";

    document.getElementById("demo").innerHTML = x + "<br>" + y;

</script>

Output:

It's alright

We are the so-called "Vikings" from the north.