点击运行
<!DOCTYPE html> <html> <body> <h1>将默认值设置为函数参数</h1> <p id="demo"></p> <script> function myFunction(x, y) { if (y === undefined) { y = 0; } return x * y; } document.getElementById("demo").innerHTML = myFunction(4); </script> </body> </html>
运行结果
