如何在javascript中获取最接近的输入类型文本值？

Question

我正在用 html 设计一个表格，它在一个 td 中包含 time picker 作为开始时间，在第二个 td 中包含第二个时间选择器作为一个 tr 中的结束时间。我想同时取两个值（开始时间和结束时间）并想计算时间差并想在第三个 td 中显示。但我无法获得特定的 td 值来计算差异。

  <table id="example1" class="machinetable" cellspacing="0" width="100%">
  <thead>
    <tr>

     <th>Sr. no.</th>
     <th>Machine Name</th>
     <th >Rate Type</th>
     <th >Rate Unit</th>
     <th >Rate</th>
     <th >Start Time</th>
     <th >End Time</th>
     <th >Total Time</th>
 </thead>
 <tbody>
    <tr role="row" class="odd">
      <td>1</td>
      <td>JCB</td>
      <td>MH23GH5477</td>
      <td>per Hour</td>
      <td>1000</td>
      <td>
          <div class="input-group"><input name="start_time" value="" class="form-control form-cont datetime start_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
        </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" ><input name="end_time" value="" onchange="calculate_time(this.value)" class="form-control form-cont datetime end_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
        </div>
      </td>
      <td class="total_time"></td>
   </tr>
   <tr role="row" class="odd">
      <td>2</td>
      <td>JCB</td>
      <td>MH2398</td>
      <td>per Hour</td>
      <td>1000</td>
      <td>
         <div class="input-group" ><input name="start_time" value="" class="form-control form-cont datetime start_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
         </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" ><input name="end_time" value="" onchange="calculate_time(this.value)" class="form-control form-cont datetime end_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
         </div>
      </td>
      <td class="total_time"></td>
   </tr>
</tbody>

Javascript 函数：

function calculate_time(time)
{
   var endtime1 = time;
   var starttime1= 
   $(this).closest('td').prev('td').find("input[name=start_time]")val();
   alert(starttime1);
   alert(endtime1);
}

出现错误：

开始时间未定

我是 js 新手。

Answer 1

由于您在函数内使用当前元素的引用，因此首先在函数中传递this 而不是this.value。您还错过了val() 之前的点 (.)。

现在改变如下函数：

function calculate_time(time){
  var endtime1 = time.value;
  var starttime1= $(time).closest('td').prev('td').find('.start_time').val();
  alert(starttime1);
  alert(endtime1);
}

function calculate_time(time){
   var endtime1 = time.value;
   var starttime1= $(time).closest('td').prev('td').find('.start_time').val();
   alert(starttime1);
   alert(endtime1);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table id="example1" class="machinetable" cellspacing="0" width="100%">
  <thead>
    <tr>

     <th>Sr. no.</th>
     <th>Machine Name</th>
     <th >Rate Type</th>
     <th >Rate Unit</th>
     <th >Rate</th>
     <th >Start Time</th>
     <th >End Time</th>
     <th >Total Time</th>
 </thead>
 <tbody>
    <tr role="row" class="odd">
      <td>1</td>
      <td>JCB</td>
      <td>MH23GH5477</td>
      <td>per Hour</td>
      <td>1000</td>
      <td>
          <div class="input-group"><input name="start_time" value="" class="form-control form-cont datetime start_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
        </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" ><input name="end_time" value="" onchange="calculate_time(this)" class="form-control form-cont datetime end_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
        </div>
      </td>
      <td class="total_time"></td>
   </tr>
   <tr role="row" class="odd">
      <td>2</td>
      <td>JCB</td>
      <td>MH2398</td>
      <td>per Hour</td>
      <td>1000</td>
      <td>
         <div class="input-group" ><input name="start_time" value="" class="form-control form-cont datetime start_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
         </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" ><input name="end_time" value="" onchange="calculate_time(this)" class="form-control form-cont datetime end_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
         </div>
      </td>
      <td class="total_time"></td>
   </tr>
</tbody>

Answer 2

您的代码中有几个问题：

1. 您可以在calculate_time() 函数中传递元素的引用，这样您就可以使用该元素来查找它附近的其他元素。目前calculate_time() 中的$(this) 引用的是Window 对象，而不是您的实际元素。
2. 在calculate_time() 函数中传递元素引用后使用$(elem).closest('td').prev('td').find("input[name=start_time]").val()。

以下是获取 start_time 和 end_time 值的工作示例，您仍然需要将其与日期字段集成，并在使用以下代码获取日期值后计算差异：

function calculate_time(elem)
{
   var endtime1 = elem.value;
   var starttime1 = $(elem).closest('td').prev('td').find("input[name=start_time]").val();
   alert(starttime1);
   alert(endtime1);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table id="example1" class="machinetable" cellspacing="0" width="100%">
  <thead>
    <tr>

     <th>Sr. no.</th>
     <th>Machine Name</th>
     <th >Rate Type</th>
     <th >Rate Unit</th>
     <th >Rate</th>
     <th >Start Time</th>
     <th >End Time</th>
     <th >Total Time</th>
 </thead>
 <tbody>
    <tr role="row" class="odd">
      <td>1</td>
      <td>JCB</td>
      <td>MH23GH5477</td>
      <td>per Hover</td>
      <td>1000</td>
      <td>
          <div class="input-group"><input name="start_time" value="" class="form-control form-cont datetime start_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
        </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" ><input name="end_time" value="" onchange="calculate_time(this)" class="form-control form-cont datetime end_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
        </div>
      </td>
      <td class="total_time"></td>
   </tr>
   <tr role="row" class="odd">
      <td>2</td>
      <td>JCB</td>
      <td>MH2398</td>
      <td>per Hover</td>
      <td>1000</td>
      <td>
         <div class="input-group" ><input name="start_time" value="" class="form-control form-cont datetime start_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
         </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" ><input name="end_time" value="" onchange="calculate_time(this)" class="form-control form-cont datetime end_time" type="text"><span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
         </div>
      </td>
      <td class="total_time"></td>
   </tr>
</tbody>

Answer 3

在调用类似 onchange="calculate_time(this.value, '1')" 这样的函数时再传递一个参数 其中 1 是 start_time 的 id 如下所示

<input name="start_time" id="start_time1" value="" class="form-control form-cont datetime start_time" type="text">

那么你的函数看起来像：

<script>
function calculate_time(time, id)
{
//alert(id);
   var endtime1 = time;
   var starttime1= $("#start_time"+id).val();

   alert(endtime1);
   alert(starttime1);
}
</script>

希望这会有所帮助！

Answer 4

试试这个 这里没有进行验证。

  <table id="example1" class="machinetable" cellspacing="0" width="100%">
  <thead>
    <tr>

     <th>Sr. no.</th>
     <th>Machine Name</th>
     <th >Rate Type</th>
     <th >Rate Unit</th>
     <th >Rate</th>
     <th >Start Time</th>
     <th >End Time</th>
     <th >Total Time</th>
 </thead>
 <tbody>
    <tr role="row" class="odd">
      <td>1</td>
      <td>JCB</td>
      <td>MH23GH5477</td>
      <td>per Hour</td>
      <td>1000</td>
      <td>
          <div class="input-group">
          
          <input name="start_time" value="" class="form-control form-cont datetime start_time" type="text" id="time_a_1">
          
          <span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
        </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" >
            <input name="end_time" value="" onkeyup="calculate_time(1)" class="form-control form-cont datetime end_time" type="text" id="time_a_2">
            <span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
        </div>
      </td>
      <td class="total_time" id="time_a"></td>
   </tr>
   <tr role="row" class="odd">
      <td>2</td>
      <td>JCB</td>
      <td>MH2398</td>
      <td>per Hour</td>
      <td>1000</td>
      <td>
         <div class="input-group" >
         <input name="start_time" value="" class="form-control form-cont datetime start_time" type="text" id="time_b_1">
         <span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span>
         </div>
      </td>
      <td>
         <div class="form-group nomargin">
            <div class="input-group" >
            <input name="end_time" value="" onkeyup="calculate_time(2)" class="form-control form-cont datetime end_time" type="text" id="time_b_2">
            <span class="input-group-addon group-addon"><span><i class="fa fa-clock-o" aria-hidden="true"></i></span></span></div>
         </div>
      </td>
      <td class="total_time" id="time_b"></td>
   </tr>
</tbody>

<script>
function calculate_time(time)
{
if(time == 1){
start_time = document.getElementById("time_a_1").value
end_time = document.getElementById("time_a_2").value
total = start_time + end_time
document.getElementById("time_a").innerText = total;
}
else if(time == 2){
start_time = document.getElementById("time_b_1").value
end_time = document.getElementById("time_b_2").value
total = start_time + end_time
document.getElementById("time_b").innerText = total;
}
}
</script>