# jQuery應用 - 亂數產生器 (2) 如何利用 jQuery 在網頁中新增 HTML element ## random2.html ```htmlmixed= <!doctype html> <html lang="zh-TW"> <head> <!-- Required meta tags --> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <!-- Bootstrap CSS --> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous"> <!-- 引用自已定義的CSS --> <link rel="stylesheet" href="./css/temp.css"> <title>亂數產生器</title> </head> <body> <div class="container"> <!-- 標題 --> <div class="row"> <div class="col"> <div class="jumbotron"> <h1 class="display-4">亂數產生器</h1> </div> </div> </div> <!-- 表單 --> <div class="row"> <div class="col"> <form> <div class="form-group row"> <label for="inputNumber" class="col-sm-2 col-form-label">要產生多少個1到49的亂數</label> <div class="col-sm-10"> <input type="number" class="form-control" id="inputNumber" placeholder="請輸入要產生多少個亂數" value="1"> </div> </div> <div class="form-group row"> <div class="col-sm-10"> <button id="main" type="button" class="btn btn-primary">產生</button> </div> </div> <div class="form-group row"> <label for="outputRandom" class="col-sm-2 col-form-label">產生出來的亂數</label> <div class="col-sm-10"> <input type="text" readonly class="form-control-plaintext" id="outputRandom" placeholder=""> </div> </div> </form> </div> </div> <div class="row"> <div class="col"> <footer> copyright &copy; 2019 前端程式設計 </footer> </div> </div> </div> <!-- Optional JavaScript --> <!-- jQuery first, then Popper.js, then Bootstrap JS --> <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script> <!-- 引用自己寫的 js --> <script src="./js/random.js"></script> </body> </html> ``` ## random.js ```javascript= var rand = (start, end) => { var r n = end - start + 1 //求亂數的範圍 r = Math.random() * n // 放大 r = Math.floor(r) // 去除小數點 r += start // 位移 return r } // 當HTML文件載入完成時執行 $(() => { // 這裡就是程式的開始 console.log('JS 正常執行') // 當 id=main 的 html element 被按到的時候執行 $('#main').on('click', () => { console.log('按到了喔') var n = $('#inputNumber').val() var str = '' for (i = 1; i <= n; i++) { str += rand(1, 49) str += ' ' } $('#outputRandom').val(str) }) }) ``` ###### tags: `前端程式設計` `108-1`