当按钮没有未定义时,我遇到此错误:Uncaught TypeError: Cannot set property 'onclick' of undefined
。有人可以帮我找到错误并进行修复。我对Java比较陌生。 HTML,Javascript和输出都包括在内。谢谢HTML(此处没有脚本链接标签):
<h1 id="change">Color change</h1>
<button class="color-change" data-colour="green">Green</button>
<button class="color-change" data-colour="red">Red</button>
<button class="color-change" data-colour="blue">Blue</button>
JavaScript
document.addEventListener("DOMContentLoaded", function(){
buttons = document.querySelectorAll(".color-change");
var i;
for(i=0; i<buttons.length; ++i){
let button = buttons[i];
console.log(button);
document.button.onclick = function(){
document.querySelector("#change").style.color = document.buttons[i].dataset.colour;
}
}
});
输出:
<button class="color-change" data-colour="green">Green</button>
index.js:24 Uncaught TypeError: Cannot set property 'onclick' of undefined
at HTMLDocument.<anonymous> (index.js:24)
您不需要调用document.
来引用您声明的变量button
和buttons
。