[javascript] How can I select an element by name with jQuery?

Have a table column I'm trying to expand and hide:

jQuery seems to hide the td elements when I select it by class but not by element's name.

For example, why does:

$(".bold").hide(); // selecting by class works
$("tcol1").hide(); // select by element name does not work

Note the HTML below, the second column has the same name for all rows. How could I create this collection using the name attribute?

<tr>    
    <td>data1</td>
    <td name="tcol1" class="bold"> data2</td>
</tr>
<tr>    
    <td>data1</td>
    <td name="tcol1" class="bold"> data2</td>
</tr>  
<tr>    
    <td>data1</td>
    <td name="tcol1" class="bold"> data2</td>
</tr>

If you have something like:

<input type="checkbox" name="mycheckbox" value="11" checked="">
<input type="checkbox" name="mycheckbox" value="12">

You can read all like this:

jQuery("input[name='mycheckbox']").each(function() {
    console.log( this.value + ":" + this.checked );
});

The snippet:

jQuery("input[name='mycheckbox']").each(function() {_x000D_
  console.log( this.value + ":" + this.checked );_x000D_
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input type="checkbox" name="mycheckbox" value="11" checked="">_x000D_
<input type="checkbox" name="mycheckbox" value="12">

Performance

Today (2020.06.16) I perform tests for chosen solutions on MacOs High Sierra on Chrome 83.0, Safari 13.1.1 and Firefox 77.0.

Conclusions

Get elements by name

• getElementByName (C) is fastest solution for all browsers for big and small arrays - however I is probably some kind of lazy-loading solution or It use some internal browser hash-cache with name-element pairs
• mixed js-jquery solution (B) is faster than querySelectorAll (D) solution
• pure jquery solution (A) is slowest

Get rows by name and hide them (we exclude precalculated native solution (I) - theoretically fastest) from comparison - it is used as reference)

• surprisingly the mixed js-jquery solution (F) is fastest on all browsers
• surprisingly the precalculated solution (I) is slower than jquery (E,F) solutions for big tables (!!!) - I check that .hide() jQuery method set style "default:none" on hidden elements - but it looks that they find faster way of do it than element.style.display='none'
• jquery (E) solution is quite-fast on big tables
• jquery (E) and querySelectorAll (H) solutions are slowest for small tables
• getElementByName (G) and querySelectorAll (H) solutions are quite slow for big tables

Details

I perform two tests for read elements by name (A,B,C,D) and hide that elements (E,F,G,H,I)

• small table - 3 rows - you can run test HERE
• big table - 1000 rows - you can run test HERE

Snippet below presents used codes

//https://stackoverflow.com/questions/1107220/how-can-i-select-an-element-by-name-with-jquery#

// https://jsbench.me/o6kbhyyvib/1
// https://jsbench.me/2fkbi9rirv/1

function A() {
  return $('[name=tcol1]');
}

function B() {
  return $(document.getElementsByName("tcol1"))
}

function C() {
  return document.getElementsByName("tcol1")
}

function D() {
  return document.querySelectorAll('[name=tcol1]')
}

function E() {
  $('[name=tcol1]').hide();
}

function F() {
  $(document.getElementsByName("tcol1")).hide();
}

function G() {
  document.getElementsByName("tcol1").forEach(e=>e.style.display='none'); 
}

function H() {
  document.querySelectorAll('[name=tcol1]').forEach(e=>e.style.display='none'); 
}

function I() {
  let elArr = [...document.getElementsByName("tcol1")];
  let length = elArr.length
  for(let i=0; i<length; i++) elArr[i].style.display='none';
}




// -----------
// TEST
// -----------

function reset() { $('td[name=tcol1]').show(); } 

[A,B,C,D].forEach(f=> console.log(`${f.name} rows: ${f().length}`)) ;

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<div>This snippet only presents used codes</div>
<table>
  <tr>    
      <td>data1</td>
      <td name="tcol1" class="bold"> data2</td>
  </tr>
  <tr>    
      <td>data1</td>
      <td name="tcol1" class="bold"> data2</td>
  </tr>  
  <tr>    
      <td>data1</td>
      <td name="tcol1" class="bold"> data2</td>
  </tr>
</table>

<button onclick="E()">E: hide</button>
<button onclick="F()">F: hide</button>
<button onclick="G()">G: hide</button>
<button onclick="H()">H: hide</button>
<button onclick="I()">I: hide</button><br>
<button onclick="reset()">reset</button>

Example results on Chrome

You can get the element in JQuery by using its ID attribute like this:

$("#tcol1").hide();

You can get the name value from an input field using name element in jQuery by:

var firstname = jQuery("#form1 input[name=firstname]").val(); //Returns ABCD_x000D_
var lastname = jQuery("#form1 input[name=lastname]").val(); //Returns XYZ _x000D_
console.log(firstname);_x000D_
console.log(lastname);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<form name="form1" id="form1">_x000D_
  <input type="text" name="firstname" value="ABCD"/>_x000D_
  <input type="text" name="lastname" value="XYZ"/>_x000D_
</form>

Frameworks usually use bracket names in forms, like:

<input name=user[first_name] />

They can be accessed by:

// in JS:
this.querySelectorAll('[name="user[first_name]"]')

// in jQuery:
$('[name="user[first_name]"]')

// or by mask with escaped quotes:
this.querySelectorAll("[name*=\"[first_name]\"]")

Personally, what I've done in the past is give them a common class id and used that to select them. It may not be ideal as they have a class specified that may not exist, but it makes the selection a hell of a lot easier. Just make sure you're unique in your classnames.

i.e. for the example above I'd use your selection by class. Better still would be to change the class name from bold to 'tcol1', so you don't get any accidental inclusions into the jQuery results. If bold does actually refer to a CSS class, you can always specify both in the class property - i.e. 'class="tcol1 bold"'.

In summary, if you can't select by Name, either use a complicated jQuery selector and accept any related performance hit or use Class selectors.

You can always limit the jQuery scope by including the table name i.e. $('#tableID > .bold')

That should restrict jQuery from searching the "world".

Its could still be classed as a complicated selector, but it quickly constrains any searching to within the table with the ID of '#tableID', so keeps the processing to a minimum.

An alternative of this if you're looking for more than 1 element within #table1 would be to look this up separately and then pass it to jQuery as this limits the scope, but saves a bit of processing to look it up each time.

var tbl = $('#tableID');
var boldElements = $('.bold',tbl);
var rows = $('tr',tbl);
if (rows.length) {
   var row1 = rows[0]; 
   var firstRowCells = $('td',row1); 
}

You can use any attribute as selector with [attribute_name=value].

$('td[name=tcol1]').hide();

You can use the function:

get.elementbyId();

You could get the array of elements by name the old fashioned way and pass that array to jQuery.

function toggleByName() {_x000D_
  var arrChkBox = document.getElementsByName("chName");_x000D_
  $(arrChkBox).toggle();_x000D_
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<html>_x000D_
  <head>_x000D_
    <title>sandBox</title>_x000D_
  </head>_x000D_
  <body>_x000D_
    <input type="radio" name="chName"/><br />_x000D_
    <input type="radio" name="chName"/><br />_x000D_
    <input type="radio" name="chName"/><br />_x000D_
    <input type="radio" name="chName"/><br />_x000D_
    <input type="button" onclick="toggleByName();" value="toggle"/>_x000D_
  </body>_x000D_
</html>

note: the only time you would have a reason to use the "name" attribute should be for checkbox or radio inputs.

Or you could just add another class to the elements for selection.(This is what I would do)

function toggleByClass(bolShow) {_x000D_
  if (bolShow) {_x000D_
    $(".rowToToggle").show();_x000D_
  } else {_x000D_
    $(".rowToToggle").hide();_x000D_
  }_x000D_
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<html>_x000D_
  <head>_x000D_
    <title>sandBox</title>_x000D_
  </head>_x000D_
  <body>_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>data1</td>_x000D_
        <td class="bold rowToToggle">data2</td>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <td>data1</td>_x000D_
        <td class="bold rowToToggle">data2</td>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <td>data1</td>_x000D_
        <td class="bold rowToToggle">data2</td>_x000D_
      </tr>_x000D_
    </table>_x000D_
    <input type="button" onclick="toggleByClass(true);" value="show"/>_x000D_
    <input type="button" onclick="toggleByClass(false);" value="hide"/>_x000D_
  </body>_x000D_
</html>

Any attribute can be selected using [attribute_name=value] way. See the sample here:

var value = $("[name='nameofobject']");

You forgot the second set of quotes, which makes the accepted answer incorrect:

$('td[name="tcol1"]') 

I've done like this and it works:

$('[name="tcol1"]')

https://api.jquery.com/attribute-equals-selector/

Here's a simple solution: $('td[name=tcol1]')