Javascript getElementsByName() 不起作用？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/6967297/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
getElementsByName() not working?
提问by sqlmole
I have a Javascript function which should update a hidden input field in my form with a number that increments every time the function is called.
我有一个 Javascript 函数，它应该使用每次调用函数时递增的数字更新表单中的隐藏输入字段。
It worked originally with getElementById()however because I had to redesign my form I cannot use the php function to assign an individual ID to the element so all I have is a unique name for that element.
它最初与getElementById() 一起使用，但是因为我必须重新设计我的表单，所以我无法使用 php 函数为元素分配一个单独的 ID，所以我只有该元素的唯一名称。
So instead I decided to use getElementsByName()from Javascript to modify the element.
因此，我决定使用Javascript 中的getElementsByName()来修改元素。
Here is the HTML of that element
这是该元素的 HTML
<input type="hidden" value="" name="staff_counter">
This is my Javascript code:
这是我的 Javascript 代码：
window.onload=function()
{
//function is activated by a form button
var staffbox = document.getElementsByName('staff_counter');
staffbox.value = s;
s++;
}
I am getting no errors on Firebug when the function is called and the input field is not getting a value given to it.
当函数被调用并且输入字段没有获得给它的值时，我在 Firebug 上没有收到任何错误。
It was working with getElementById() but why all of a sudden it does not work with getElementsByName()?
它与 getElementById() 一起工作，但为什么突然间它不适用于 getElementsByName()？
- -I have checked that it is the only unique element in the document.
- -I checked for any errors on Firebug when activating the function
- - 我已经检查过它是文档中唯一的唯一元素。
- - 我在激活功能时检查了 Firebug 上的任何错误
Here is the code I use from Codeigniter to make the element
这是我从 Codeigniter 使用的代码来制作元素
// staff_counter is name and the set_value function sets the value from what is
//posted so if the validation fails and the page is reloaded the form element does
// not lose its value
echo form_hidden('staff_counter', set_value('staff_counter'));
Thanks
谢谢
回答by Digital Plane
document.getElementsByName()returns a NodeList, so you have to access it by an index: document.getElementsByName('staff_counter')[0](depending on how many of these you have).
document.getElementsByName()返回一个NodeList，因此您必须通过索引访问它：（document.getElementsByName('staff_counter')[0]取决于您拥有的索引数量）。
You also have access to a lengthproperty to check how many Elements were matched.
您还可以访问一个length属性来检查匹配了多少元素。
回答by Louis
Just had a similar issue, I resolved it with a simple loop over the array. The code below will go through and disable all the buttons with the name of 'btnSubmit'.
刚刚有一个类似的问题，我用一个简单的数组循环解决了它。下面的代码将通过并禁用所有名为“btnSubmit”的按钮。
for (var i=0;i<document.getElementsByName('btnSubmit').length;i++){
document.getElementsByName('btnSubmit')[i].disabled=true;
}
