function toggleByClass(bolShow) {
if (bolShow) {
$(".rowToToggle").show();
} else {
$(".rowToToggle").hide();
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<title>sandBox</title>
</head>
<table>
<td>data1</td>
<td class="bold rowToToggle">data2</td>
<td>data1</td>
<td class="bold rowToToggle">data2</td>
<td>data1</td>
<td class="bold rowToToggle">data2</td>
</table>
<input type="button" onclick="toggleByClass(true);" value="show"/>
<input type="button" onclick="toggleByClass(false);" value="hide"/>
</body>
</html>
var firstname = jQuery("#form1 input[name=firstname]").val(); //Returns ABCD
var lastname = jQuery("#form1 input[name=lastname]").val(); //Returns XYZ
console.log(firstname);
console.log(lastname);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form name="form1" id="form1">
<input type="text" name="firstname" value="ABCD"/>
<input type="text" name="lastname" value="XYZ"/>
</form>
–
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';
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>
<td>data1</td>
<td name="tcol1" class="bold"> data2</td>
<td>data1</td>
<td name="tcol1" class="bold"> data2</td>
<td>data1</td>
<td name="tcol1" class="bold"> data2</td>
</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
–
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);
$to.val($from.val());
<script src="https://cdn.jsdelivr.net/npm/jquery@3/dist/jquery.min.js"></script>
<input type="text" name="foo" value="copy name='foo'">
<input type="text" disabled id="result-1" placeholder="i'm disabled">
<input type="text" name="foo[bar]" value="copy name='foo[bar]'">
<input type="text" disabled id="result-2" placeholder="i'm disabled">
<input type="button" id="copy" value="copy values">
–
