<html><body><h2>JavaScript 变量</h2><p>字符串用引号书写。</p><p>数字不带引号。</p><p id="demo"></p><script>var pi = 3.14;var person = "John Doe";var answer = 'Yes I am!';document.getElementById("demo").innerHTML =pi + "<br>" + person + "<br>" + answer;</script></body></html>