js中判斷奇偶的函式,求圓面積的函式
阿新 • • 發佈:2021-02-11
技術標籤:jsjavascriptjs
定義一個函式,判斷是否為偶數,如果是則返回true,不是則返回false
傳統方法:
程式碼:
<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>Document</title> <script type="text/javascript"> function isOdd(a){ if(a % 2 == 0) return true; else return false; } var result = isOdd(1); document.write(result); </script> </head> <body> </body> </html>
執行結果:
簡化方法(a%2==0本來就是布林判斷了):
<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>Document</title> <script type="text/javascript"> function isOdd(a){ return a % 2 == 0; } var result = isOdd(112); document.write(result); </script> </head> <body> </body> </html>
執行結果:
定義一個函式,可以根據半徑計算圓的面積,並返回計算結果
<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>Document</title> <script type="text/javascript"> function area(r){ return 3.14 * r * r; } var result = area(5); document.write("圓的面積是:" + result); </script> </head> <body> </body> </html>
執行結果: