将键eventlistener添加到上次生成的输入字段，并在键入后将其停止(Add key eventlistener to last generated input field and stop i

当我单击一个Button时，我的dom中将生成一个非特定数量的输入字段的形式加上一个空输入字段。

我想在最后生成的空输入字段中添加类似按键事件的内容。

当我开始输入时，在最后一个空输入字段中，应附加另一个输入字段。 这个新的附加输入字段应该得到keypress eventlistener，我所在的输入字段应该松开keypress eventlistener。

这是我做的方式（ 编辑：添加为代码片段）：

$(document.body).on("input", ".service-input:last", function (e) {
    var lastInput = $(".elementCtr.input-ctr input").last(),
            inputID = (parseInt(lastInput.attr('name')) + 1);
    $("#providerServicesForm .inputs").append('<div class="elementCtr input-ctr"><input id="service_' + inputID + '" type="text" value="" name="' + inputID + '"></div>');
  }); 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<form accept-charset="UTF-8" name="providerServicesForm" id="providerServicesForm" method="post">
  <div class="inputs">
    <div class="elementCtr input-ctr"><input type="text" name="1" value="test1" id="service_1" class="service-input"></div>
    <div class="elementCtr input-ctr"><input type="text" name="2" value="test2" id="service_2" class="service-input"></div>
    <div class="elementCtr input-ctr"><input type="text" name="3" value="test3" id="service_3" class="service-input"></div>
    <div class="elementCtr input-ctr"><input type="text" name="3" value="" id="service_3" class="service-input"></div
  </div>
</form> 
  
 
 
 这到目前为止工作正常。 但是我当然希望只有第一次按键才会发生这种情况。 
 
 
 
 按下一个键后，它应该停止添加文本字段。 但是当我在新添加的（最后一个）文本字段中输入内容时，它应该再次添加文本字段。 但按键等后只有1个Textfield ... 
 
 
 输入后我无法停止事件监视器。 
 
 
 Keypress是否适用于移动设备？ 
 
When I click a Button, a form of an unspecific number of input fields will be generated in my dom plus an empty input Field.
 
I want to add something like a keypress event to the last generated empty input field.
 
When I start typing, into the last empty input field, another input field should append. This new appended input field should get the keypress eventlistener and the input field I am in should loose the keypress eventlistener.
 
Here's how I did it(EDIT: added as code snippet):
 
 
 
  
  
$(document.body).on("input", ".service-input:last", function (e) {
    var lastInput = $(".elementCtr.input-ctr input").last(),
            inputID = (parseInt(lastInput.attr('name')) + 1);
    $("#providerServicesForm .inputs").append('<div class="elementCtr input-ctr"><input id="service_' + inputID + '" type="text" value="" name="' + inputID + '"></div>');
  }); 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<form accept-charset="UTF-8" name="providerServicesForm" id="providerServicesForm" method="post">
  <div class="inputs">
    <div class="elementCtr input-ctr"><input type="text" name="1" value="test1" id="service_1" class="service-input"></div>
    <div class="elementCtr input-ctr"><input type="text" name="2" value="test2" id="service_2" class="service-input"></div>
    <div class="elementCtr input-ctr"><input type="text" name="3" value="test3" id="service_3" class="service-input"></div>
    <div class="elementCtr input-ctr"><input type="text" name="3" value="" id="service_3" class="service-input"></div
  </div>
</form> 
  
 
 
This works fine so far. But of course I want that this happens only with the first keypress.
 
 
 
After pressing a key, it should stop adding textfields. But when I type something in to the new added (last) textfield it should add a textfield again. But only 1 Textfield after pressing a key etc...
 
 
I can't stop the eventlistener after typing.
 
 
Does Keypress work with mobile devices?
 

                
最满意答案
                
                    
                        
 关于这种处理程序的好处是，如果使用新的最后一个元素更新DOM，处理程序会立即切换到新元素 - 不需要使用.off或.one 。 
 
 
 
  
  
$(document.body).on("input", ".service-input:last", function () {
    var inputID = (parseInt($(this).attr('name')) + 1);
    $("#providerServicesForm .inputs").append('<div class="elementCtr input-ctr"><input id="service_' + inputID + '" class="service-input" type="text" value="" name="' + inputID + '"></div>');
  }); 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<form accept-charset="UTF-8" name="providerServicesForm" id="providerServicesForm" method="post">
  <div class="inputs">
    <div class="elementCtr">
      <input id="service_0" type="text" class="service-input" value="" name="0">
    </div>
    <div class="elementCtr">
      <input id="service_1" type="text" class="service-input" value="" name="1">
    </div>
    <div class="elementCtr">
      <input id="service_2" type="text" class="service-input" value="" name="2">
    </div>
  </div>
</form> 
  
 
 
 一种可能的增强是检测空字符串并删除新添加的输入。 
The great thing about this sort of handler, is if you update the DOM with a new last element, the handler immediately switches to the new element - no need to use .off or .one.
 
 
 
  
  
$(document.body).on("input", ".service-input:last", function () {
    var inputID = (parseInt($(this).attr('name')) + 1);
    $("#providerServicesForm .inputs").append('<div class="elementCtr input-ctr"><input id="service_' + inputID + '" class="service-input" type="text" value="" name="' + inputID + '"></div>');
  }); 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<form accept-charset="UTF-8" name="providerServicesForm" id="providerServicesForm" method="post">
  <div class="inputs">
    <div class="elementCtr">
      <input id="service_0" type="text" class="service-input" value="" name="0">
    </div>
    <div class="elementCtr">
      <input id="service_1" type="text" class="service-input" value="" name="1">
    </div>
    <div class="elementCtr">
      <input id="service_2" type="text" class="service-input" value="" name="2">
    </div>
  </div>
</form> 
  
 
 
One possible enhancement is to detect an empty string and remove the newly added input.