Question

我是JavaScript的新手，我不知道如何处理此作业-

”修改页面以隐藏所有图像，直到单击“开始”按钮为止。单击后，开始按钮应变为停止按钮并显示单词“停止”，单击时将隐藏图像。一旦隐藏该按钮应该变成“开始”按钮并显示“开始”一词，然后像“开始”按钮一样再次动作。请注意，有一个按钮可以更改文本，其作用取决于当前是停止还是开始显示。”

我知道我应该使用显示/隐藏效果，但是我真的不知道如何将它们应用于代码？

    <!doctype html>
    <html>
    <head>
        <title>Slide Show</title>
        <!-- will remove the 404 error for favicon.ico from console -->
        <link rel="shortcut icon" href="favicon.ico" type="image/x-icon">
        <link rel="icon" href="favicon.ico" type="image/x-icon">

        <!-- using jQuery -->
        <link href="simpleImageV2.css" rel="stylesheet" type="text/css">
        <script src="jquery-3.3.1.min.js"></script>
        <script src="simpleImagesV2.js"></script>
    </head>

    <body bgcolor="black" onload="preLoadImages()">
        <div id="setSize">
        <img name="campus_pic" src="images/fall_1_480x640.png" width="480" height="640">
        </div>
        <br />
        <br />
        <button id="startShow">Start the Show</button>
        <button id="stopShow">Stop the Show</button>
    </body>
    </html>

JavaScript-

/*global $ */
var i = 0, myTimer, campus;

function preLoadImages() {
    "use strict";
    if (document.images) {
        campus = new Array();  // global variable
        campus[0] = new Image();
        campus[0][0] = "images/fall_1_480x640.png";
        campus[0][1] = "480";
        campus[0][2] = "640";
        campus[1] = new Image();
        campus[1][0] = "images/winter_1_640x480.png";
        campus[1][1] = "640";
        campus[1][2] = "480";
        campus[2] = new Image();
        campus[2][0] = "images/spring_1_640x480.png";
        campus[2][1] = "640";
        campus[2][2] = "480";
        campus[3] = new Image();
        campus[3][0] = "images/summer_1_480x640.png";
        campus[3][1] = "480";
        campus[3][2] = "640";
    } else {
        window.alert("This browser does not support images");
    }
}

Answer 1

您可以像下面这样使用jQuery：

else

function method Fib (n : int) : int
  decreases n
{
   if n < 2 then n else Fib (n - 2) + Fib (n - 1)
}

method Main ()
{
  print Fib (3);
}

JavaScript-显示/隐藏功能

1 个答案: