The HTML file:

<html>
<head>
<script>
    "use strict"

    //x = 7

    let y = 5;
    console.log(y, "is of type", typeof y);
    y  = "hello world";
    console.log(y, "is of type", typeof y);
    y = ['a','b','c']
    console.log(y, "is of type", typeof y);

    let z
    console.log("z is ", z, "typeof z is ", typeof z)
    console.log('typeof z === "undefined"', typeof z === "undefined")
    console.log('z === undefined ', z === undefined);

    let name = "bob";
    let otherName = name;
    otherName = otherName + "'s"
    otherName += " house";
    console.log("name = ", name, "otherName = ",otherName);

    console.log("The length of '"+name+"' is "+name.length)
    console.log("The first letter of '"+name+"' is "+ name[0])


    console.log('checking "3"== 3', "3" == 3)
    console.log('checking "3"=== 3', "3" === 3)

    var a = 3;
    var b  = 2;

    console.log("a = ", a, " b = ", b);

    console.log("a/b = ", a/b, "a%b = ", a%b);

    console.log(parseInt("3.14"), "is 3.14");
    console.log(parseFloat("3.14"), "is 3.14");
    console.log(String(3.14));

    function StringPass(a, b="hello") {
        console.log("\tIn String Pass a = '"+a+"'");
        console.log("\tIn String Pass b = '"+b+"'");
	a = "world";
	b = "";
    }


    let str1 = "blank string";
    StringPass(str1);
    console.log("str1 = '" + str1 + "'");

    let str2 = "greeting";
    StringPass(str1, str2);

    let list1=[1,2,3];
    StringPass(list1);
    console.log("list1 = '" + str1 + "'");



</script>
</head>
<body>
</body>
</html>