<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<script>
let x1 = ""; // string
let x2 = 0; // number
let x3 = false; // boolean
const x4 = {}; // Object object
const x5 = []; // Array object
const x6 = /()/; // RegExp object
const x7 = function(){}; // function
// すべての種類を表示
document.getElementById("demo").innerHTML =
"x1: " + typeof x1 + "<br>" +
"x2: " + typeof x2 + "<br>" +
"x3: " + typeof x3 + "<br>" +
"x4: " + typeof x4 + "<br>" +
"x5: " + typeof x5 + "<br>" +
"x6: " + typeof x6 + "<br>" +
"x7: " + typeof x7 + "<br>";
</script>
