Javascript 中的 getElementsByClassName 调用有什么问题？
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What is wrong with this getElementsByClassName call in Javascript?
提问by David Willis
I am trying to access the width of a div to put in a cookie. This is the div:
我正在尝试访问要放入 cookie 的 div 的宽度。这是div：
<div class="tab_panel" style="width:600px">
It is the only div with this class name. It is not an option to specify a unique id for the div. This is the code I have been using in an event to call it but it gives an error:
它是唯一具有此类名称的 div。为 div 指定唯一 id 不是一个选项。这是我在一个事件中使用的代码来调用它，但它给出了一个错误：
document.getElementsByClassName(tab_panel).style.width
I know Firefox supports getElementsByClassName, so what am I doing wrong?
我知道 Firefox 支持getElementsByClassName，所以我做错了什么？
回答by Enrico Murru
It's a string:
这是一个字符串：
document.getElementsByClassName("tab_panel")[0].style.width
Bye
再见
P.S. It's an array
PS 这是一个数组
回答by kennebec
document.getElementsByClassName("tab_panel")returns a collection of nodes, the first of which is referred to by document.getElementsByClassName("tab_panel")[0].
document.getElementsByClassName("tab_panel")返回节点集合，其中第一个由 引用document.getElementsByClassName("tab_panel")[0]。
If the node you are searching does not have an inline style="width:' assignment, an empty string is returned from document.getElementsByClassName("tab_panel")[0].style.width.
如果您搜索的节点没有内联 style="width:' 赋值，则从 返回一个空字符串document.getElementsByClassName("tab_panel")[0].style.width。
回答by Sarfraz
Missing quotes:
缺少报价：
document.getElementsByClassName('tab_panel').....
You should iterate over all elements like this:
您应该像这样迭代所有元素：
var elms = document.getElementsByClassName('tab_panel');
for(var i = 0 ; i < elms.length; i++)
{
alert(elms[i].style.width);
}
回答by Justin Ethier
Try saying:
试着说：
document.getElementsByClassName("tab_panel")
