Develop Reference

How to get any column of any row of a Table in HTML?

Suppose there is Table with variable number of rows of fixed number of columns, and suppose each row has a button too, now I want to select for example a column's value(let's say this selected column is textarea, so I select it's content) when that row's button is clicked.
For example in above image I want that if submit is pressed than all data of 'textarea' of corresponding row should be stored in a variable.

You can use the jQuery closest() function to find an element near the clicked button. Add click handlers to the buttons and then traverse up to find the textarea.
$('.button').on("click",function(){
var thisRowsTA = $(this).closest("textarea");
console.log($(thisRowsTA).val());
});

A simply way is to:
Put an ID pattern to your textareas, like: txt_area_1, txt_area_2, txt_area_3.
Then, on the Click Event of your buttons, make them catch the corresponding textarea in their row. Use the ID patterns to do this.
Post your code for further help.

You will need to ad an event handler for each button. Inside of that you can write something like this.
function eventHandler(e){
var row = this; // start at the button
while(row.nodeName != 'TR' && row.parent){
// go up till we find the row
row = row.parent;
}
var textArea = row.querySelector('textarea');
var value = textArea.value;
// do something with supplied feedback.
}
In order to attach the handlers, you would do something like this.
function attachTableEvents(){
var table = document.querySelector('table'); // or more specific selector if needed
var buttons = table.querySelectorAll('button');
for (var i = buttons.length; i--;){
buttons[i].addEventListener(eventHandler);
}
}

Counting on the DOM structure is really BAD.
I would put an attribute in my controls that holds the line number. Then when clicking an element you can easily query the DOM by element type and the property value to get any elements in this line.
Later if you change to DIVs or change structure your will still run correctly

Insert Row(child) in table using JavaScript

I have table containing 4 main rows and one (expand or collapse) button.On click of (expand or collapse) button i want to insert one more row in middle of all rows(which result in total 8 rows) by iterating the table rows.How to do this using Javascript?See the image below.Any suggestion.
This is the code i have return on click of Expand or Collapse button,
jQuery('#btnId').click(function() {
var that = this;
$("#example tbody tr").each(function(i) {
//what code need to add here
});
});

Due to the fact, that you haven't provided a code example, I only can suggest one way to achieve this.
You can determine the row above the row you'll want to insert by an id on the tr or by a css selector like :nth-of-type(4) for example.
After that, you can use this row as jquery element (example: $("tr#yourrow")) and append a row after it using append().
Example: $("tr#yourrow").append("<tr>... your row definition ...</tr>")
Based on the updated question:
jQuery('#btnId').click(function() {
var that = this;
$("#example tbody tr").each(function(i, object) {
$(object).after("<tr>... your row definition ...</tr>")
});
});
The row definition should be done by yourself. I don't know the logic behind the iteration in your case. But I think you'll get it. :)

Highlighting row of a HTML table which is populated using AJAX return data

How to get row value of a table on mouse click? Data in this table is populated from the data returned using AJAX.
Below is the code which is not working:
$('table#tblBdy tbody tr').click(function() {
$('tr').click(function () {
var tableData = $(this).closest("tr").children("td").map(function() {
return $(this).text();
}).get();
$('#bx1txt').val($.trim(tableData[0]));
$('#bx2txt').val($.trim(tableData[1]));
$('#oldqty').val($.trim(tableData[1]));
});

I'm not sure I completely follow your question, your title and descriptions seem to conflict. Are you looking to get the value you a specific cell on click? Your question says you want the value of a row...
If I understand it correctly, you either want the value of a specific cell when it is clicked, or you want to highlight the row of that cell that you are clicking.
I have setup a codepen http://codepen.io/anon/pen/oXNeMx with a simple solution.
Depending on how the table is generated, you can put that javascript code into it's own function and call that function whenever you have new AJAX data so that the click handler gets bound to the table and elements.
//handles table cell click events
$('td').click(function(){
//updates the value
var cellValue = $(this).html();
//find the row of table where cell was clicked
var tr = $(this).closest('tr');
//removes select class from all rows
$(tr).siblings().removeClass('highlight');
//adds class to highlight selected row
tr.addClass('highlight');
});

The reason your code is not working is because you attach an event handler to some elements, but then you replace those elements with new ones from the AJAX call.
You need to set an event handler on an element that will not change, for example, the table (if you table gets replaced in its entirely, you need to find a higher ancestor that never changes).
// ancestor event real selector
$('#tblBdy').on('click', 'tbody td', function() {
// Same code as yours in the handlers
});

Passing a value from one input to another in jQuery

jsFiddle for reference:
http://jsfiddle.net/UxQV7/
What I'm trying to do is if the user clicks on "Add" on the 2nd row, the new form element is displayed underneath.
The user then types a number in that new form element, clicks the "Add" button and then that number will be populated in the Serial# input of the 2nd row and the new form element then is hidden.
The part I'm having trouble is once the user types in the number to that new form element, how do I know to send it back to the 2nd row.
Thanks very much.

You could do:
var index;
$(".addSerial").click(function(){
index = $(this).closest('tr').index();
console.log(index);
$("#serialAdd").toggle();
});
$("#submitSerial").click(function(){
$('table tr:eq('+index+') input:first').val($("#serialToAdd").val());
$("#serialAdd").toggle();
});
fiddle here http://jsfiddle.net/qWGKq/

You're going to have to store a reference value somewhere (in a global variable, for example) to indicate which <a> was clicked to display the Serial Number entry <div> or create it dynamically on the fly and destroy it afterwards.

Save the current row in a variable, and then filter the textbox out of it to set the value to: http://jsfiddle.net/UxQV7/1/.
var currentRow; // will be <tr> of row where user has clicked on Add
$(".addSerial").click(function(){
currentRow = $(this).parents('tr'); // set current row
$("#serialAdd").toggle();
});
$("#submitSerial").click(function(){
$("#serialAdd").toggle();
currentRow.find(':text:eq(2)').val($('#serialToAdd').val());
// find correct textbox in row and copy value
});

You can use jQuery's prev() to get the target input and save it:
var activeField;
$(".addSerial").click(function(){
$("#serialAdd").toggle();
activeField = $(this).prev();
return false;
});
$("#submitSerial").click(function(){
$("#serialAdd").toggle();
activeField.val( $("#serialToAdd").val() );
$("#serialToAdd").val("")
});
Demo: http://jsfiddle.net/7Xykw/

when these controls are rendered you need to have a serial number to each control in id that way you can easily identify controls and add values.
Check this working sample . http://jsfiddle.net/UxQV7/18/

adding rows dynamically using onclick function in javascript

Am having a task in some onclick functions.I had a table in which each column contains a dropdown list or text box. one of the column contains a button.If i click that button the row with dropdownlist,textboxes including add button have to dynamically add as the next row.how can i do this?which will be better javascript or jquery..plz help me out..

You can try the following
in onclick of the row add the following function
function cloneRow(event){
var tar_ele;
if ($.browser.msie) {
// IE takes SRCELEMENT for event source.
// may the force shred IE.
tar_ele = $(event.srcElement);
} else {
tar_ele = $(event.target);
}
// Now take the parent of the clicked item as the item is a button in a row
var row = tar_ele.parent();
// Now clone the row and add it to the parent.
row.clone().appendTo(row.parent());
}
Hope this helps.

You can try this:
$('button-id').click(function() {
$('container-id').after('<input /><select />');
});
Something like that, will have you added a new line with input and select boxes to the end of the container or your table.