jquery如何從最後tr得到值輸入？

Question

   <tr id="subpage_title1"> 
          <td class="order minus">1</td> 
          <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
          <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td>    
          <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="1" value="3000"></td> 
          <td></td> 
       </tr><tr id="subpage_title2"> 
          <td class="order ">2</td> 
          <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
          <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td>    
          <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="2" value="3000"></td> 
          <td></td> 
       </tr> 
       <tr id="subpage_title3" style="display: table-row;"> 
          <td class="order">3</td> 
          <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
          <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td> 
          <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="3" value="3000"></td> 
          <td><a class="btn-remove-tr btn btn-small">Delete Floor</a></td> 
       </tr> 
       <tr id="subpage_title4" style="display: table-row;"> 
         <td class="order">4</td><td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
         <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td> 
         <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="4" value="2000"></td> 
         <td><a class="btn-remove-tr btn btn-small">Delete Floor</a></td> 
       </tr> 

我累了，從過去的TR獲得價值輸入類=「和」只請了一些一個可以幫助我！

如果我刪除一行，我必須獲得最後的值，如果我添加其他行，我必須獲得最後的值

Answer 1

console.log($('table tr:last td input.sum').val())

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 
<table> 
 
<tr id="subpage_title1"> 
 
          <td class="order minus">1</td> 
 
          <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
 
          <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td>    
 
          <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="1" value="3000"></td> 
 
          <td></td> 
 
       </tr><tr id="subpage_title2"> 
 
          <td class="order ">2</td> 
 
          <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
 
          <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td>    
 
          <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="2" value="3000"></td> 
 
          <td></td> 
 
       </tr> 
 
       <tr id="subpage_title3" style="display: table-row;"> 
 
          <td class="order">3</td> 
 
          <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
 
          <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td> 
 
          <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="3" value="3000"></td> 
 
          <td><a class="btn-remove-tr btn btn-small">Delete Floor</a></td> 
 
       </tr> 
 
       <tr id="subpage_title4" style="display: table-row;"> 
 
         <td class="order">4</td><td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
 
         <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td> 
 
         <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="4" value="2000"></td> 
 
         <td><a class="btn-remove-tr btn btn-small">Delete Floor</a></td> 
 
       </tr> 
 
       
 
       <table>

嘗試。

Answer 2

試試這個：

$("tr:last td input.sum") 

Answer 3

的HTML：

<table> 
     <tr id="subpage_title1"> 
        <td class="order minus">1</td> 
        <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
        <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td>    
        <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="1" value="3000"></td> 
        <td></td> 
     </tr><tr id="subpage_title2"> 
        <td class="order ">2</td> 
        <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
        <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td>    
        <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="2" value="3000"></td> 
        <td></td> 
     </tr> 
     <tr id="subpage_title3" style="display: table-row;"> 
        <td class="order">3</td> 
        <td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
        <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td> 
        <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="3" value="3000"></td> 
        <td><a class="btn-remove-tr btn btn-small">Delete Floor</a></td> 
     </tr> 
     <tr id="subpage_title4" style="display: table-row;"> 
       <td class="order">4</td><td><input type="checkbox" name="checkF[]" checked="" value=""> Front (A)</td> 
       <td><input type="checkbox" name="checkB[]" value=""> Back (C)</td> 
       <td><input id="hfloor" class="sum" name="hfloor[]" type="number" min="100" max="5000" step="4" value="2000"></td> 
       <td><a class="btn-remove-tr btn btn-small">Delete Floor</a></td> 
     </tr> 
    </table>  

腳本：

$(function(){ 
var value = $("tr:last td input.sum").val() 
console.log(value) 
}) 

小提琴here