xxxxxxxxxx<html><head><meta charset="utf-8"><title>W3Cschool教程(w3cschool.cn)</title></head><body><p> typeof 操作符返回变量或表达式的类型。</p><button onclick="myFunction()">点我</button><p id="demo"></p><script>function myFunction() { var y = "John"; var x = + y; document.getElementById("demo").innerHTML = typeof x + "<br>" + x;}</script></body></html>