How to compare the two given string using javascript?

Html page:

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

JavaScript page:

<script>

function myFunction()

{

    var str1 = "ab";

    var str2 = "cd";

    var n = str1.localeCompare(str2);

    document.getElementById("demo").innerHTML = n;

}

</script>

Output:

-1

·         Returns -1 if str1 is sorted before str2

·         Returns 0 if the two strings are equal

·         Returns 1 if str1 is sorted after str2