Question

我無法獲取用於清除文本的按鈕。所以當我點擊圖片時，按鈕和文本會顯示，當我點擊按鈕時，它會消失，但文本不會。

<script type="text/javascript"> 
    function song(animal, sound) { 
    document.getElementById("buttonAppear").innerHTML = '<button type="button" onclick="buttonFunction(); clear();">Clear</button>'; 
    document.getElementById("verse").innerHTML += "<br>Old MacDonald had a farm, E-I-E-I-O.<br>And on that farm he had a " + animal + ", E-I-E-I-O.<br>with a " + sound + "-" + sound + " here and a " + sound + "-" + sound + " there,<br> here a " + sound + " there a " + sound + " everywhere a " + sound + "-" + sound + "."; 
    } 

    function clear() { 
    document.getElementById("verse").innerHTML = ""; 
    } 

    function buttonFunction() { 
    document.getElementById("buttonAppear").innerHTML = ""; 
    } 
</script> 
</head> 
<main> 
    <h1>The Animals Game</h1> 

    <img src="cat.jpg" title="Cat" alt="Cat" height="200" width="200" onclick="song('CAT', 'MEOW') ;"> 
    <img src="cow.jpg" title="Cow" alt="Cow" height="200" width="200" onclick="song('COW', 'MOO') ;"> 
    <img src="dog.jpg" title="Dog" alt="Dog" height="200" width="200" onclick="song('DOG', 'WOOF') ;"> 


    <p id="verse"></p> 
    <div id="buttonAppear"></div> 

Answer 1

事實證明，'clear'作爲全局引用已經被作爲文檔對象的屬性。

此處瞭解詳情：

Is "clear" a reserved word in Javascript?

你應該改變你的函數名稱到別的東西，像clearParagraph（）

Answer 2

當onclick處理程序是叫你不引用您的clear功能，而是document.clear函數（Is "clear" a reserved word in Javascript?）。嘗試重命名你的函數或集點擊事件處理程序，而不是使用onclick屬性（你可以在這裏閱讀更多關於onclick="" vs event handler，有一個類似的問題被列）