<html><body><h2>JavaScript typeof</h2><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 0 + "<br>" + typeof 314 + "<br>" +typeof 3.14 + "<br>" +typeof (3) + "<br>" +typeof (3 + 4);</script></body></html>