javascript - 创建手动幻灯片时出错

Question

出于某种原因，我在我的 javascript 文件中的一行中不断收到以下错误(我在下面指出了该行)。这是我的 HTML:

<div class="slideshowproject">
    <button id="rightbutton" onclick=manualslideshow("rightbutton,projectslides1")>></button>
    <img class="projectslides1" src="Project Images\\HarrisonHealthClinic\\Render 1-1.jpg">
    <img class="projectslides1" src="Project Images\\HarrisonHealthClinic\\Render 2-1.jpg">
    <img class="projectslides1" src="Project Images\\HarrisonHealthClinic\\Render 3-1.jpg">
    <button id="leftbutton" onclick=manualslideshow("leftbutton","projectslides1")><</button>
    <script>manualslideshow("","projectslides1")</script>
</div>

和我的javascript:

var imagenumber=0;
function manualslideshow(buttonid,slideshowclass){
    var pictures=document.getElementsByClassName(slideshowclass);
    for (i=0;i<pictures.length;i++){
        pictures[i].style.display="none";
    }
    if (buttonid=="rightbutton"){
        imagenumber++;
    }
    else if (buttonid=="leftbutton"){
        imagenumber--;
    }
    if (imagenumber>pictures.length){
        imagenumber=1;
    }
    if (imagenumber<1){
        imagenumber=pictures.length;
    }
    pictures[imagenumber-1].style.display="block";
}

出于某种原因，“.style.display="block";"在脚本的最后一行出现错误:

navigationbar.js:68 Uncaught TypeError: Cannot read property 'style' of undefined
    at manualslideshow (navigationbar.js:68)
    at HTMLButtonElement.onclick (clinic.html:42)

Javascript 第 68 行是最终闭合花括号之前的最后一行，html 中的第 42 行是“右键”行(复制过来的 HTML 中的第 2 行)

感谢您的所有帮助和时间。

Answer 1

查看您的代码，我发现从 Html 文件调用“manualslideshow”方法时出错。 (即第 42 行)。请看下面的代码。我已经从("rightbutton,projectslides1") 到 ("rightbutton","projectslides1")

<div class="slideshowproject">
    <button id="rightbutton" onclick=manualslideshow("rightbutton","projectslides1")>></button>
    <img class="projectslides1" src="Project Images\\HarrisonHealthClinic\\Render 1-1.jpg">
    <img class="projectslides1" src="Project Images\\HarrisonHealthClinic\\Render 2-1.jpg">
    <img class="projectslides1" src="Project Images\\HarrisonHealthClinic\\Render 3-1.jpg">
    <button id="leftbutton" onclick=manualslideshow("leftbutton","projectslides1")><</button>
    <script>manualslideshow("","projectslides1")</script>
</div>