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How to find the value from a row of table depending on the row of a button I clicked

No jQuery involve pls. I am just started learning javascript.
I want to find the class='id' of the table when I clicked on the class='detail' button.
I manage to point to class='id' but I can't get the value out of it, why?
var button = document.getElementsByClassName("detail");
for (var i in button) {
button[i].onclick = function() {
var row = this.closest("tr");
var id = row.getElementsByClassName("id");
var value = id.innerText;
console.log(id);
console.log(value); //show undefined here
}
}
<table>
<tbody>
<tr>
<td class="id">123</td>
<td class="name">abc</td>
<td><button class="detail">detail</button></td>
</tr>
<tr>
<td class="id">456</td>
<td class="name">def</td>
<td><button class="detail">detail</button></td>
</tr>
</tbody>
</table>
where would need to change? I must use class here, as the table generated through javascript. thanks.

getElementsByClassName returns HTMLCollection containing multiple matching elements. Like an array, you can access the first element in the collection with [0]
var button = document.getElementsByClassName("detail");
for (var i in button) {
button[i].onclick = function () {
var row = this.closest("tr");
var id = row.getElementsByClassName("id");
var value = id[ 0 ].innerText;
console.log(id);
console.log(value);
}
}
<table>
<tbody>
<tr>
<td class="id">123</td>
<td class="name">abc</td>
<td><button class="detail">detail</button></td>
</tr>
<tr>
<td class="id">456</td>
<td class="name">def</td>
<td><button class="detail">detail</button></td>
</tr>
</tbody>
</table>

Get table row value based on button click using Jquery/Javascript

I need to get the table row value from onclick event. Below the table, I am using
Group name|Manage group
Test 1 | Button
Test 2 | Button
If I click 'Button' from the table row, I need to get the respective group name value from the table row.
Below the script, I am trying. But it is printing only the first group name value "Test 1" for both buttons.
var table = document.getElementById("user_table");
var rows = table.rows;
for (var i = 1; i < rows.length; i++) {
rows[i].onclick = (function (e) {
var rowid = (this.cells[0].innerHTML);
var j = 0;
var td = e.target;
while( (td = td.previousElementSibling) != null )
j++;
alert(rows[1].cells[j].innerHTML);
});
}
alert(rows[1].cells[j].innerHTML) printing group name value Test 1 and if I click second row button it is showing Test 1 only.But I need to get Test 2 if I click second row button.
Html file
<table id="user_table" style='overflow-x:scroll;overflow-y:scroll;width:100%;height:auto' class="table table-bordered" >
<thead>
<tr class="info">
<th>Group Name</th>
<th>User Group</th>
</tr>
</thead>
<tbody id="table_body">
<br>
<% #array.each do |user| %>
<tr>
<td >
<%=user['group_name']%>
</td>
<td>
<button id='manageusrbtn' name="button" type="button" class="editbtn" onclick="manageUserGroups()" style="background-color: #008CBA; color: white; border-radius: 6px;" >Manage User Groups</button>
</td>
<% end %>
</tr>
</tbody>
</table>

I would suggest to attach the click event handler to the button and not to each cell.
For this you can use:
querySelectorAll
forEach
addEventListener
closest
The snippet:
var table = document.querySelectorAll('#user_table tr button');
table.forEach(function(ele) {
ele.addEventListener('click', function (e) {
var rowid = (this.closest('td').previousElementSibling.innerHTML);
console.log(rowid);
})
});
<table id="user_table">
<tr>
<th>Group name</th>
<th>Manage group</th>
</tr>
<tbody>
<tr>
<td>Test 1</td>
<td><button>Button</button></td>
</tr> <tr>
<td>Test 2</td>
<td><button>Button</button></td>
</tr>
</tbody>
</table>

In the below code I want to get the index value of rs using its Id and want to get its position

<table>
<tr>
<td id="1">Adi</td>
<td id="2">Aman</td>
</tr>
</table>
In the above code, I want to know the position of Aman using its id

You can try something like this:
html:
<table id="myTable">
<tr>
<td id="1">Adi</td>
<td id="2">Aman</td>
</tr>
</table>
js:
function getIdFromTable(searchValue)
{
var t = document.getElementById("myTable");
var trs = t.getElementsByTagName("tr");
var tds = null;
for (var i=0; i<trs.length; i++)
{
tds = trs[i].getElementsByTagName("td");
for (var n=0; n<tds.length;n++)
{
if (tds[n].innerText === searchValue) {
return tds[n].id;
}
}
}
}
getIdFromTable('Aman'); // will return 2

Easiest way to find position by id would be using prevAll().length. Something like this:
function findPositionById(id){
return $('#mytable').find('#'+id).prevAll().length
}
console.log('Adi Position', findPositionById(1));
console.log('Aman Position', findPositionById(2));
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<table id="mytable">
<tr>
<td id="1">Adi</td>
<td id="2">Aman</td>
</tr>
</table>

Calculating the value of a table

I have got a table.
I have assigned a different value to each of the lines
<table id="number1">
<tr>
<td id="value1">My Table</td>
</tr>
</table>
<script>
window.onload = function() {
document.getElementById("value1").value = "100"
</script>
I need to be able to get a value for the table "number 1" by adding the different rows of the table through Javascript.

var x=document.getElementById("number1");
var y= x.rows[0].cells[0].innerHTML=100;
<table id="number1">
<tr>
<td id="value1">My Table</td>
</tr>
</table>

You can use jquery
for(i=1;i<100000;i++){
$("#value"+i).html(i);
}

Try this
var total=0;
var last =1000000;
for(var i=1;i<parseInt(last);i++){
var id ="value" + i;
var element= document.getElementById(id);
if(element!= null){
document.getElementById(id).innerHTML=i + "00";
total=parseInt(total)+parseInt(element.innerHTML);
}
else
i=last;
}
document.getElementById("result").innerHTML="sum is =" + total;
<table id="number1">
<tr>
<td id="value1">My Table value 1 </td>
<td id="value2">My Table value 2 </td>
</tr>
</table>
<div id="result"></div>

Remove table row by finding content with clause

I have this code:
<table>
<tbody>
<tr><td>Table 1</td></tr>
</tbody>
</table>
<table>
<tbody>
<tr>
<td align="left">Number</td>
<td><b>33</b></td>
</tr>
<tr>
<td width="150" align="left">Field</td>
<td>XXXX</td>
</tr>
<tr>
<td align="left">Select: </td>
<td colspan="4">
<select name="status" size="1">
<option selected="selected" value="2">one</option>
<option value="1">two</option>
</select>
</td>
</tr>
</tbody>
</table>
and i want to remove this line by searching "Field" with pure Javascript:
<tr>
<td width="150" align="left">Field</td>
<td>XXXX</td>
</tr>
when there is a 33, 66 or 99 in this line from my 2nd table:
<tr>
<td align="left">Number</td>
<td>33</td>
</tr>
The problem is that i don't have any id's or classes for identification! i want to use the code with Greasemonkey.
Here you can see a JSFIDDLE of my table.
And here you can see on JSFIDDLE how it should look.
Best regards bernte

Here you go:
var disallowedValues = ['33', '66', '99'];
var cols = document.getElementsByTagName('td');
var colslen = cols.length;
var i = -1;
var disallowedTable;
while(++i < colslen){
// look for the td where the disallowed values are
if(disallowedValues.indexOf(cols[i].innerHTML) >= 0)
{
// get the table where the disallowed values is
disallowedTable = cols[i].parentNode.parentNode.parentNode;
// break the cicle to stop looking for other rows
//break;
}
}
// look for the 'Field' value only on the table that has the disallowed value
var cols = disallowedTable.getElementsByTagName('td');
cols = disallowedTable.getElementsByTagName('td');
colslen = cols.length;
i = -1;
while(++i < colslen){
// look for the td where the 'Field' value is
if(cols[i].innerHTML == 'Field')
{
// get the tr for such td
var deletionTR = cols[i].parentNode;
//delete that tr
deletionTR.parentNode.removeChild(deletionTR);
// break the cicle to stop looking for other rows
break;
}
}
You can always do a simpler version if jquery is an option.