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[英]Javascript Function Not Defined On Click Event, But Works on Page Load?
[英]Javascript function is not defined on click event
编辑:我做了一个js小提琴与答案,仍然返回未定义的函数。
我正在努力找出为什么我的函数返回未定义的原因。 我的html:
<div class="slideshow">
<div class="slide">
<div class="work-info col-3">
<div class="block-orange">
<h3>Work</h3>
<p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Nisi ipsum iure esse nemo facere ea, iste deserunt odit provident labore exercitationem nihil, laborum, sit vel nostrum illo ducimus possimus dolorum.</p>
</div>
</div>
</div>
<div class="slide">
</div>
<div class="slide">
</div>
<div class="slide">
</div>
<div class="dot-cont">
<div class="dot" onclick="clickChangeSlide(0)"></div>
<div class="dot" onclick="clickChangeSlide(1)"></div>
<div class="dot" onclick="clickChangeSlide(2)"></div>
<div class="dot" onclick="clickChangeSlide(3)"></div>
</div>
<button class="arrow-button left-arrow" onclick="clickChangeSlide(i-1)"><</button>
<button class="arrow-button right-arrow" onclick="clickChangeSlide(i+1)">></button>
</div>
该js正在页面底部加载。 JS:
document.addEventListener("DOMContentLoaded", function(event) {
let i = -1;
let time = 5000;
let slideTimer;
let slides = document.getElementsByClassName('slide');
let slideDots = document.getElementsByClassName('dot');
function clickChangeSlide(n){
clearTimeout(slideTimer);
changeSlide(n, true);
}
function changeSlide(n = i, manual = false){
for(let j = 0; j < slides.length; j++){
if(j == i) {
slides[j].classList.add('prev-slide');
slides[j].classList.remove('active-slide');
slideDots[j].classList.remove('active-dot');
continue;
}
slideDots[j].classList.remove('active-dot');
slides[j].classList.remove('prev-slide');
slides[j].classList.remove('active-slide');
}
if(manual){
if(n < 0) i = slides.length - 1
else if(n > slides.length - 1) i = 0
else i = n
}else i = i < slides.length - 1 ? i+1 : 0;
slides[i].classList.add('active-slide');
slideDots[i].classList.add('active-dot');
slideTimer = setTimeout(changeSlide, time);
}
window.onload = changeSlide();
});
我试图删除DomcontentLoaded,因为我认为这可能会影响到它,但没有成功。 当我单击按钮时,不会触发ClickChangeSlide。 有任何想法吗?
您正在回调中定义clickChangeSlide()
,因此它的作用域在整个文档中都不存在。
您必须在回调之外定义它,例如:
let i = -1;
let time = 5000;
let slideTimer;
let slides = document.getElementsByClassName('slide');
let slideDots = document.getElementsByClassName('dot');
document.addEventListener("DOMContentLoaded", function(event) {
window.onload = changeSlide();
});
function clickChangeSlide(n){
clearTimeout(slideTimer);
changeSlide(n, true);
}
function changeSlide(n = i, manual = false){
for(let j = 0; j < slides.length; j++){
if(j == i) {
slides[j].classList.add('prev-slide');
slides[j].classList.remove('active-slide');
slideDots[j].classList.remove('active-dot');
continue;
}
slideDots[j].classList.remove('active-dot');
slides[j].classList.remove('prev-slide');
slides[j].classList.remove('active-slide');
}
if(manual){
if(n < 0) i = slides.length - 1
else if(n > slides.length - 1) i = 0
else i = n
}else i = i < slides.length - 1 ? i+1 : 0;
slides[i].classList.add('active-slide');
slideDots[i].classList.add('active-dot');
slideTimer = setTimeout(changeSlide, time);
}
您的DOM尝试访问在DOM构建时不可用的功能,对此负责onclick=clickChangeSlide(0)...
将两个函数changeSlide(...)
和clickChangeSlide(...)
放在实际DOMContentLoaded
事件侦听器的外部,以在DOM构建期间访问这些函数。
它可能看起来像这样:
<div class="slideshow">
<div class="slide">
<div class="work-info col-3">
<div class="block-orange">
<h3>Work</h3>
<p>Lorem ipsum...</p>
</div>
</div>
</div>
<div class="slide"></div>
<div class="slide"></div>
<div class="slide"></div>
<div class="dot-cont">
<div class="dot" onclick="clickChangeSlide(0)"></div>
<div class="dot" onclick="clickChangeSlide(1)"></div>
<div class="dot" onclick="clickChangeSlide(2)"></div>
<div class="dot" onclick="clickChangeSlide(3)"></div>
</div>
<button class="arrow-button left-arrow" onclick="clickChangeSlide(i-1)"><</button>
<button class="arrow-button right-arrow" onclick="clickChangeSlide(i+1)">></button>
</div>
您的JavaScript代码应如下所示:
let i = -1;
var slideTimer;
let time = 5000;
let slides = document.getElementsByClassName('slide');
let slideDots = document.getElementsByClassName('dot');
function changeSlide(n = i, manual = false) {
for (let j = 0; j < slides.length; j++) {
if (j == i) {
slides[j].classList.add('prev-slide');
slides[j].classList.remove('active-slide');
slideDots[j].classList.remove('active-dot');
continue;
}
slideDots[j].classList.remove('active-dot');
slides[j].classList.remove('prev-slide');
slides[j].classList.remove('active-slide');
}
if (manual) {
if(n < 0) i = slides.length - 1
else if(n > slides.length - 1) i = 0
else i = n
} else i = i < slides.length - 1 ? i+1 : 0;
slides[i].classList.add('active-slide');
slideDots[i].classList.add('active-dot');
slideTimer = setTimeout(changeSlide, time);
};
function clickChangeSlide(n) {
clearTimeout(slideTimer);
changeSlide(n, true);
};
document.addEventListener("DOMContentLoaded", function(event) {
window.onload = changeSlide();
});
您还必须更改变量i, slides, slideDots, ...
因为在声明变量之前访问了changeSlide
。 使用<script src="javascript.js"></script>
将javascript代码加载到html代码的顶部,否则DOM无法将任何函数初始化为div元素的onload
函数。
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