Javascript this.element.queryselectoral(';li';)与this.element.children的比较,其中所有子项都是li
当所有子元素都是'li'元素时,为什么this.el.children在this.el.queryselectoral('li')时不起作用;是吗 例如:Javascript this.element.queryselectoral(';li';)与this.element.children的比较,其中所有子项都是li,javascript,this,children,wai-aria,selectors-api,Javascript,This,Children,Wai Aria,Selectors Api,当所有子元素都是'li'元素时,为什么this.el.children在this.el.queryselectoral('li')时不起作用;是吗 例如: function RadioGroup(id) { this.el = document.querySelector(id); this.buttons = slice(this.el.querySelectorAll('.radio')); this.focusedIdx = 0; this.focusedButton = this.but
function RadioGroup(id) {
this.el = document.querySelector(id);
this.buttons = slice(this.el.querySelectorAll('.radio'));
this.focusedIdx = 0;
this.focusedButton = this.buttons[this.focusedIdx];
this.el.addEventListener('keydown', this.handleKeyDown.bind(this));
this.el.addEventListener('click', this.handleClick.bind(this));
this.el.setAttribute('role', 'radiogroup');
// This works
this.el.querySelectorAll('li').forEach(function (item){
item.setAttribute('role', 'radio');
});
// But this doesn't
this.el.children.forEach(function (item){
item.setAttribute('role', 'radio');
});
}
这里是HTML:
<ul id="group1" class="radiogroup">
<li class="radio">Water</li>
<li class="radio">Tea</li>
<li class="radio">Coffee</li>
<li class="radio">Cola</li>
<li class="radio">Ginger Ale</li>
</ul>
水
茶
咖啡
可乐
姜汁汽水
元素。querySelectorAll
返回一个节点列表
,其中包含forEach
方法,其中as节点。children
是一个HTMLCollection
且不包含forEach
[1] [2] [3]
[4]
元素。querySelectorAll
返回一个节点列表
,其中包含forEach
方法,其中as节点。children
是一个HTMLCollection
且不包含forEach
[1] [2] [3]
[4] 使用ES6的spread操作符,您可以使两者以相同的方式工作
function RadioGroup(id) {
this.el = document.querySelector(id);
this.buttons = slice(this.el.querySelectorAll('.radio'));
this.focusedIdx = 0;
this.focusedButton = this.buttons[this.focusedIdx];
this.el.addEventListener('keydown', this.handleKeyDown.bind(this));
this.el.addEventListener('click', this.handleClick.bind(this));
this.el.setAttribute('role', 'radiogroup');
// This works
[...this.el.querySelectorAll('li')].forEach(function (item){
item.setAttribute('role', 'radio');
});
// And this too ;-)
[...this.el.children].forEach(function (item){
item.setAttribute('role', 'radio');
});
}
使用ES6的spread操作符,您可以使两者以相同的方式工作
function RadioGroup(id) {
this.el = document.querySelector(id);
this.buttons = slice(this.el.querySelectorAll('.radio'));
this.focusedIdx = 0;
this.focusedButton = this.buttons[this.focusedIdx];
this.el.addEventListener('keydown', this.handleKeyDown.bind(this));
this.el.addEventListener('click', this.handleClick.bind(this));
this.el.setAttribute('role', 'radiogroup');
// This works
[...this.el.querySelectorAll('li')].forEach(function (item){
item.setAttribute('role', 'radio');
});
// And this too ;-)
[...this.el.children].forEach(function (item){
item.setAttribute('role', 'radio');
});
}
因为
HTMLCollection
s没有forEach
方法。使用(点击F12
)阅读任何错误。可能重复的我们也可以说,任何时候有人在了解节点列表和HTMLCollection之间的差异时,都是该问题的重复。谢谢你!因为HTMLCollection
s没有forEach
方法。使用(点击F12
)阅读任何错误。可能重复的我们也可以说,任何时候有人在了解节点列表和HTMLCollection之间的差异时,都是该问题的重复。谢谢你!