javascript 如何按类而不是“GetElementById”获取元素？
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How can i get elements by class instead of "GetElementById"?
提问by Fábio Pavani
So, this is the code:
所以，这是代码：
<a id="link" href="https://url.com/">URL:</a>
<input id="value"/>
<script type="text/javascript">
var link= document.getElementById('link');
var input= document.getElementById('value');
input.onchange=input.onkeyup= function() {
link.search= 'extendurl/'+encodeURIComponent(input.value);
};
</script>
this is working, but i need to use the class instead of the ID. I try this:
这是有效的，但我需要使用类而不是 ID。我试试这个：
<script type="text/javascript">
var link= document.getElementByClassName("link")[0];
var input= document.getElementByClassName("value")[0];
input.onchange=input.onkeyup= function() {
link.search= 'extendurl/'+encodeURIComponent(input.value);
link.firstChild.data= link.href;
};
</script>
<a class="link" href="https://url.com/">URL:</a>
<input class="value"/>
i don't know why, but this isn't working.
我不知道为什么，但这不起作用。
Someone?
有人吗？
回答by Denys Séguret
The precise name is important.
准确的名称很重要。
Change
改变
getElementByClassName
to
到
getElementsByClassName
There's a sbecause there might be more than one element with a give class, contrary to elements with a specific id.
有一个是s因为可能有多个元素具有一个给定类，与具有特定 id 的元素相反。
回答by scrblnrd3
There can be many elements with the exact same class names, so you have to adjust it for that
可以有许多具有完全相同类名的元素，因此您必须为此进行调整
instead of
代替
getElementByClassName
you have to do
你必须做
getElementsbyClassName("someclass");
and it will return an array of all of them
它将返回所有这些的数组
