<!DOCTYPE html> <html> <body> <h1>JavaScript 函数</h1> <p>函数可以在表达式中使用。</p> <p id="demo"></p> <script> function myFunction(a, b) { return a * b; } var x = myFunction(4, 3) * 2; document.getElementById("demo").innerHTML = x; </script> </body> </html>