jQuery获取最接近的td文本值

Question

dears i have the following html

<tbody>
  <tr>
    <td class="text-center"><input type="text" class="form-control cardSerialNumber"></td>
    <td class="text-center"><button type="button" onclick="validateCardBeforeAssigning();" class="btn btn-success"><span style="color : white" class="glyphicon glyphicon-check"></span></button>
    </td>
  </tr>
  <tr>
    <td class="text-center"><input type="text" class="form-control cardSerialNumber"></td>
    <td class="text-center"><button type="button" onclick="validateCardBeforeAssigning();" class="btn btn-success"><span style="color : white" class="glyphicon glyphicon-check"></span></button>

    </td>
  </tr>
</tbody>

So after clicking the btn i want to get the text (class cardSerialNumber) value from the same tr with closet td

i tried the following function but getting undefined always

function validateCardBeforeAssigning() {
  alert($(this).closest('tr').find('.cardSerialNumber').val());
}

your support, please

Answer 1

I would certainly suggest using event handlers instead of an inline onclick . Give your buttons a unique class and apply the following jQuery:

<button type="button" class="btn btn-success assign-card">

$(".assign-card").on("click", function() {
  alert($(this).closest('tr').find('.cardSerialNumber').val());
});

Demo:

 $(".assign-card").on("click", function() { alert($(this).closest('tr').find('.cardSerialNumber').val()); }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <table> <tbody> <tr> <td class="text-center"><input type="text" class="form-control cardSerialNumber"></td> <td class="text-center"><button type="button" class="btn btn-success assign-card"><span style="color : white" class="glyphicon glyphicon-check">Assign</span></button> </td> </tr> <tr> <td class="text-center"><input type="text" class="form-control cardSerialNumber"></td> <td class="text-center"><button type="button" class="btn btn-success assign-card"><span style="color : white" class="glyphicon glyphicon-check">Assign</span></button> </td> </tr> </tbody> </table> 

---

If you were intent on simply fixing the code you have, which I don't recommend, you could do the following:

<button type="button" onclick="validateCardBeforeAssigning(this);" class="btn btn-success">

function validateCardBeforeAssigning(btn) {
    alert($(btn).closest('tr').find('.cardSerialNumber').val());
}

By changing your function to pass this , you get a reference to the button, whereas your use of this was not referring to any element.

Demo:

 function validateCardBeforeAssigning(btn) { alert($(btn).closest('tr').find('.cardSerialNumber').val()); } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <table> <tbody> <tr> <td class="text-center"><input type="text" class="form-control cardSerialNumber"></td> <td class="text-center"><button type="button" onclick="validateCardBeforeAssigning(this);" class="btn btn-success"><span style="color : white" class="glyphicon glyphicon-check">Assign</span></button> </td> </tr> <tr> <td class="text-center"><input type="text" class="form-control cardSerialNumber"></td> <td class="text-center"><button type="button" onclick="validateCardBeforeAssigning(this);" class="btn btn-success"><span style="color : white" class="glyphicon glyphicon-check">Assign</span></button> </td> </tr> </tbody> </table> 

Answer 2

Remove your inline JavaScript and instead use:

$('td.text-center button').click(function(){
  alert( $(this).closest('tr').find('.cardSerialNumber').val() );
})

You didn't pass a reference to the element you were clicking on your way so the function had no idea what this referred to

Answer 3

You could also get the event (passed automatically from JS) inside the function, and then get the target of the event (your clicked button)

function validateCardBeforeAssigning(ev) {
  var target = ev.target;
  alert($(target).closest('tr').find('.cardSerialNumber').val());
}