getElementsByName（）不工作？ [英] getElementsByName() not working?

问题描述

我有一个Javascript函数，它应该更新隐藏的输入字段在我的形式，每次调用函数时递增一个数字。

strong> getElementById（）但是因为我不得不重新设计我的形式我不能使用PHP函数分配一个单独的ID的元素，所以我有一个唯一的名称为该元素。

因此，我决定使用Javascript中的 getElementsByName（）来修改元素。

 < input type =hiddenvalue =name =staff_counter> 
  

这是我的Javascript代码：

  window.onload = function（）
 {
 
 //函数由表单按钮激活
 
 var staffbox = document .getElementsByName（'staff_counter'）; 
 staffbox.value = s; 
 
 
 s ++; 
} 
  

当调用函数时，Firebug没有错误，

它使用getElementById（），但是为什么突然不能使用getElementsByName（）？

• - 我已检查它是文档中唯一的唯一元素。



• 
  
  
  

  以下是Codeigniter使用的代码：

  
  
  $ b b $ b

    // staff_counter是名称，set_value函数从
   //发布的值设置值，如果验证失败，页面重新加载表单元素
   //不会丢失它的值
   
   echo form_hidden（'staff_counter'，set_value（'staff_counter'））; 
    

  感谢

  解决方案

  document.getElementsByName（）返回一个数组，所以你必须通过索引访问它： document.getElementsByName（'staff_counter' ）[0] （取决于你有多少）。

  
  
  

  您还可以访问 属性来检查匹配的元素数量。

  
  

  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.

  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.

  So instead I decided to use getElementsByName() from Javascript to modify the element.

  Here is the HTML of that element

    <input type="hidden" value="" name="staff_counter">
  

  This is my Javascript code:

  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.

  It was working with getElementById() but why all of a sudden it does not work with 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

  Here is the code I use from Codeigniter to make the element

  // 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

  解决方案

  document.getElementsByName() returns an array, so you have to access it by an index: document.getElementsByName('staff_counter')[0] (depending on how many of these you have).

  You also have access to a length property to check how many Elements were matched.

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