源代码 ：
点击运行
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>开源教程(ossoft.cn)</title> </head> <body> <p>局部变量计数。</p> <p id="demo">0</p> <script> document.getElementById("demo").innerHTML = add(); function add() { var counter = 0; function plus() {counter += 1;} plus(); return counter; } </script> </body> </html>
运行结果