​x
 
<!DOCTYPE html>
<html>
<body>
​
<p>typeof 运算符返回变量或表达式的类型。</p>
​
<p id="demo"></p>
​
<script>
document.getElementById("demo").innerHTML = 
typeof "" + "<br>" +
typeof "Bill" + "<br>" + 
typeof "Bill Gates" + "<br>" +
typeof 0 + "<br>" +
typeof 314 + "<br>" +
typeof 3.14 + "<br>" +
typeof (3.14);
</script>
</body>
</html>
​