点击运行
<!DOCTYPE html> <html> <body> <h1>JavaScript 变量</h1> <p>如果您再次声明某个 JavaScript 变量，那么它的值不会丢失。</p> <p id="demo"></p> <script> var carName = "porsche"; var carName; document.getElementById("demo").innerHTML = carName; </script> </body> </html>
运行结果
