Develop Reference

How can I perform dynamic operations on dynamically added elements?

My objective:
Filling in the 'performer-payments' table dynamically with JS/Jquery
For each (dynamically added) row in the table, one of the data cells contains a dropdown box.
This dropdown box should, when a certain option is selected, make visible another dropdown box (in the same cell). Otherwise, this second dropdown should be invisible.
Elsewhere I am accomplishing the hide/show dynamics by means of a toggleVisible function, which simply adds custom classes which is marked by css to hide or show the element.
The relevant code:
The table I want to populate:
<table id='performer-payments' class='performer-profile payments-table'>
<tr>
<th> Period </th>
<th> Amount </th>
<th> Paid? </th>
</tr>
</table>
The code that populates the table:
for (period in data['Performers'][performer]['Payments']) {
var amount = utils.calcPerformerCut(data, performer, period);
var row = "<tr>";
row += "<td> " + period + " </td>";
row += "<td> " + amount + " $ </td>";
row += "<td>";
row += "<div class='performer-profile payment-status'>";
row += data['Performers'][performer]['Payments'][period];
row += "</div>";
row += "<select id='payment-status-" + performer + "-" + period + "' class='perfomer-profile hidden-onload displayNone payment-status-menu'>";
row += "<option value='paid'>Paid</option>";
row += "<option value='unpaid'>Unpaid</option>";
row += "<option value='transfer'>Transfer to...</option>";
row += "</select>";
row += "<select id='payment-transfer-period-" + performer + "-" + period + "' class='performer-profile hidden-onload displayNone payment-period-menu'>";
for (var i=0; i < data['Periods'].length; i++) {
row += "<option value='" + period + "'>" + period + '</option>';
}
row += "</select>";
row += "</td>";
row += "</tr>";
$('#performer-payments').append(row);
$('#performer-payments').on('change', {perf: performer, per: period}, function (even) {
if (even.target.value == 'transfer') {
utils.toggleVisible($('#payment-transfer-period-' + even.data.perf + '-' + even.data.per), true);
} else {
utils.toggleVisible($('#payment-transfer-period-' + even.data.perf + '-' + even.data.per), false);
}
});
}
For reference, the code that toggles visibility:
exports.toggleVisible = function (selector, visible) {
if (visible) {
selector.removeClass('displayNone').addClass('displayBlock');
} else {
selector.removeClass('displayBlock').addClass('displayNone');
}
}
There are (at least) two issues with this:
The #payment-transfer-period-... select box is never displayed, even when the 'transfer' option is chosen in the first select box. From debugging efforts it seems to me that it could be that the #payment-transfer-period-.. for some reason is not a valid object yet, or something like that.
(Obviously, really), the on-change event is triggered N times (N=number of periods) because I am just telling the program to trigger whenever something in the table changes. I would like it to trigger only for the relevant dropdown, but when I tried adding the #payment-status-... as a selector to the .on() function, it made it never trigger.
Note: I welcome feedback on this in general - I am an experienced programmer but have very little experience with HTML/JS/Jquery. Further, I have decided to not use templates for this project since I am trying to learn the basics, so if you get pancreatitis from seeing the way I am 'dynamically' adding the rows to the table, I apologize but it is partly intentional.
Other than that, please ask for clarifications if something is not clear here.
Edit: Here is the relevant part of the data structure:
data = {
'Performers': {
'Dira Klaggen': {
'Payments': {
'Q1': 'Paid',
'Q2': 'Paid',
'Q3': 'Unpaid'
},
},
'Holden Bolden': {
'Payments': {
'Q2': 'Transferred to Q3',
'Q3': 'Unpaid'
}
},
'Manny Joe': {
'Payments': {
'Q1': 'Paid',
'Q2': 'Unpaid',
'Q3': 'Unpaid',
}
}
},
'Periods': [
'Q1',
'Q2',
'Q3'
]
}

You do not attach the change handler to the right element. I should be the first select in the row... Instead of the whole table.
Try this change handler:
$('#performer-payments').find('#payment-status-' + performer + '-' + period).on('change', function(){
if ($(this).val() == 'transfer') {
$(this).next('select').show();
} else {
$(this).next('select').hide();
}
});
Second approach:
You could simplify that by using a class instead of a "complicated" unique id for the first select.
Say you use the class "payment-status":
The handler would be:
$('#performer-payments').on('change', '.payment-status', function(){
if ($(this).val() == 'transfer') {
$(this).next('select').show();
} else {
$(this).next('select').hide();
}
});
And this handler can be out of the row appending loop because it uses delegation.

Let's clean up your code by doing the following things:
Use classes instead of ugly IDs.
Use data-attributes or hidden input fields to hold extra information.
Use event delegation to bind dynamically-created elements. Inside the event handler, use tree traversal methods to limit the scope of the search based on the current element this.
Let's apply these things.
Build each row like this. {PLACEHOLDER} is where you put your variable stuff like you have in your code.
<tr>
<td>{PERIOD}</td>
<td>{AMOUNT} $ </td>
<td>
<div class='performer-profile payment-status'>
{SOMETHING-RELATING-TO-PERFORMER-PAYMENT-PERIOD}
</div>
<!-- remove ID -->
<!-- store performer and period in data-attributes -->
<select class='perfomer-profile hidden-onload displayNone payment-status-menu' data-performer='{PERFORMER}' data-period='{PERIOD}'>
<option value='paid'>Paid</option>
<option value='unpaid'>Unpaid</option>
<option value='transfer'>Transfer to...</option>
</select>
<!-- remove ID -->
<select class='performer-profile hidden-onload displayNone payment-period-menu'>
<option value='{PERIOD}'>{PERIOD}</option>
<option value='{PERIOD}'>{PERIOD}</option>
<option value='{PERIOD}'>{PERIOD}</option>
<!-- etc -->
</select>
</td>
</tr>
In your JavaScript, create a delegated event handler. Note the syntax.
$(function () {
// ...
for (period in data['Performers'][performer]['Payments']) {
// build and append row
}
// create delegated event handler once and outside FOR loop
$(document).on('change', '.payment-status-menu', function () {
// get the current status menu
var statusMenu = $(this);
// find its related period menu
var periodMenu = statusMenu.closest('tr').find('.payment-period-menu');
// toggle its visibility
periodMenu.toggle(this.value == 'Transfer');
// of course, this could be a one-liner
//$(this).closest('tr').find('.payment-period-menu').toggle(this.value == 'Transfer');
});
});
It doesn't seem like you need (2.) but if you do, within the event handler, use statusMenu.data('performer') or statusMenu.data('period') to get its performer and period values. You could also do this.dataset.performer or this.dataset.period.

Get Select Value and Option from Specific Table Row and Column with Javascript or JQuery

I have a table that has rows appended to it. Each row has a select in column 2 {0, 1, [2]}. I am trying to get the text/value/option of the select using JavaScript or JQuery. This seems like it should be something easy but for the life of me I cannot figure out a way to get the select element in the selected row & column. Any help would be greatly appreciated.
Here is my table.
<div id="table_container">
<table id="computer_table" class="service_table">
<thead id="header_container">
<th class="table_header">COMPUTER NAME</th>
<th class="table_header">LIVE/HIDE</th>
<th class="table_header">MODE</th>
<th class="table_header">RUN</th>
</thead>
<tbody id="table_body">
</tbody>
</table>
</div>
Here is my JavaScript that adds rows to the table. Rows contain a select in column 2.
row = $('<tr class="row_white"><td class="tb_pc_name">' + value.pc_name + '</td><td class="tb_live_hide">LIVE</td><td class="tb_mode">' +
'<select id="select_mode" class="select_dropdown">' +
'<option value="0">0 - DEFAULT</option>' +
'<option value="1">1 - CLEAN UP</option>' +
'<option value="2">2 - SIGN IN</option>' +
'<option value="3">3 - SIGN OUT</option>' +
'<option value="4">4 - UPDATE IPSW</option>' +
'<option value="5">5 - OPEN DMG DIRECTORY</option>' +
'</select></td>' +
'<td class="tb_btn"><button type="button" id="btn_run">RUN</button></td></tr>');
$("#computer_table").append(row);
After all rows have been appended, the user can make a selection from the select. There is a button in column 3 that when clicked should show an alert with the select option and value of the select on the same row. The code below should show the selected option and/or value of the select in the row of the cell that is clicked. I can get the row and column but cannot get the value of the select.
$("#computer_table td").click(function() {
var table = document.getElementById('computer_table');
var column_num = parseInt( $(this).index() );
var row_num = parseInt( $(this).parent().index() );
alert('test');
/*Error here.*******************************************************************************************/
var combo = table.rows[row_num + 1].cells[2].getElementById('select_mode');
//$("#select_mode option:contains("?").attr('selected', 'selected');
alert(combo.value);
});

If you changed your buttons to use a class rather than an id they could be triggered with this:
$("#computer_table").on("click", "button.btn_run", function(e) {
alert($(this).parent().prev().children().find(":selected").text());
});

First of all there is something wrong with youre code that add the row. Every ID must be unique and it's not the case. Try using a counter (or something else) to avoid that like this:
var numberRowAdded = 0;
row = $('<tr class="row_white"><td class="tb_pc_name">' + value.pc_name + '</td><td class="tb_live_hide">LIVE</td><td class="tb_mode">' +
'<select id="select_mode'+ numberRowAdded +'" class="select_dropdown">' +
'<option value="0">0 - DEFAULT</option>' +
'<option value="1">1 - CLEAN UP</option>' +
'<option value="2">2 - SIGN IN</option>' +
'<option value="3">3 - SIGN OUT</option>' +
'<option value="4">4 - UPDATE IPSW</option>' +
'<option value="5">5 - OPEN DMG DIRECTORY</option>' +
'</select></td>' +
'<td class="tb_btn"><button type="button" id="btn_run'+ numberRowAdded +'">RUN</button></td></tr>');
$("#computer_table").append(row);
numberRowAdded++;
Then to select what you want :
$("#computer_table td").click(function() {
alert($(this).find(".select_dropdown").val());
});
Hope this help.

try passing in the ID onClick:
$("#computer_table td").click(function(this.id){ }
Just make sure all your cells have an ID.
Here is W3 example on enclosures and encapsulation. This is useful for giving all your elements a different ID. W3 encapsulation example
Adding elements with eventlisteners attached, and passing in a unique id!!
*Note: this is not an exact fix for your code. This should however aid you in understanding.
/*use this function to create unique id's*/
var add = (function () {
var counter = 0;
return function () {return counter += 1;}
})();
/*grab your table*/
var table =document.getElementById("computer_table");
/* create an element, set it's attributes*/
var newRow = document.createElement("th");
newRow.setAttribute("class", "table_header");
newRow.setAttribute("id", "table_header"+add());
/*add the event listener*/
newRow.addEventListener("click",function(this.id){ /* YOUR CODE HERE */ });
/*append to your table*/
table.appendChild(newRow);

Select the option dynamically using Jquery

I am designing a dynamic HTML for Select Option like below:
item += "<td class='ddl' style='width:40%;'>";
item += "<select>"
item += " <option id='list' name='selector' value=" + select + ">" + select + "</option>";
for (var l = 0; l < array.length; l++) {
item += " <option class='ddl' value=" + array[l] + ">" + array[l] + "</option>";
}
item += "</select>";
if ("One"!= '') {
$('#list').val("One");
}
item += "</td>";
The above code creates a dynamic HTML like below:
<select disabled="">
<option select="" value="Please" name="selector" id="list">Please Select</option>
<option value="One" class="ddl">One</option>
<option value="Two" class="ddl">Two</option>
</select>
I want to set the value of the Select to "One" dynamically.
NOTE: The code is not inside document.ready, as I cant keep the code inside ready().
Might be I am assigning the value to the Select before it is revdered on the page. Please suggest me.

You need to call the javaScript to select the value after the dropdown(select) is added to the page. For example if the html is
<div id="myContainer" />
Then the javascript should be like
var item = "";
//Insert your code to create item
item +="<select id='mySelect'>";
item +='<option select="" value="Please" name="selector" id="list">Please Select</option>';
item +='<option value="One" class="ddl">One</option> ';
item +='<option value="Two" class="ddl">Two</option>';
item +='</select>';
$('#myContainer').append(item); //Add to html
//Now the id "mySelect" is available
$('#mySelect').val('One')
I've added a jsFiddle to demonstrate this at http://jsfiddle.net/taleebanwar/n9vCb/

You could also set a selected attribute on the corresponding option tag as you create the select dynamically.

If you are using jQuery then why don't you utilize the library for creating the select, for example, using something like this (Example):
var numbers = ['one', 'two', 'three', 'four', 'five'];
var select = $('<select/>', {id:'list', name:'selector'});
$.each(numbers, function(key, value) {
var text = value[0].toUpperCase() + value.substr(1);
var option = $("<option/>", { class:'ddl', value: value, text: text });
select.append(option);
});
select.val('two').appendTo('body');
I've appended the select into body but you may append it into a td and you can achieve it, give it a try, create the td same way and insert the select in the td and then insert the td in the table. Also you may check this answer.

Trying to connect a dynamically created select element (tag) with options to a dynamically created table row

The first block of code is a working example of what I want the variable select to do. the var Select is there to be a td in the variable tr. the variable tr is used 2 times in this code. once to to append the tr when the table has html and another time when it doesn't have any html. the reason is because if doesn't have html it should append the header and the row with the select element and the rest of the data that's supposed to be on the row and if does have html it should only append the row to prevent repetition of the header. so I would like a nice clean variable named tr that will be append every time the users invokes it. jsfidle if you click on the drop down you could select the item and the new row will appear.
$('#autocomplete').autocomplete({
lookup: currencies,
onSelect: function (suggestion) {
var thehtml = '<strong>Item:</strong> ' + suggestion.value + ' <br> <strong>price:</strong> ' + suggestion.data + "<br>" + suggestion.divs;
var tableheader = ($("<thead>")
.append($("<tr>")
.append($("<th>Item</th><th>Qty</th><th>Price</th>")))
)
var select = " <select class = 'select'><option value='volvo>Volvo</option> <option value='saab'>Saab</option> <option value='mercedes'>Mercedes</option> <option value='audi'>Audi</option> </select>"
var tr = "<tr><td>"+ suggestion.value + "</td><td>" +select +"</td></tr>"
if($(".table").html().length <= 0)
{
$('.table').append($("<table>")).append(tableheader).append(tr);
}else{
if($(".table").html().length > 0){
$(".table").append(tr)
}
}
The thing is I want the select element to be made up dynamically so i tried something and I cant figure out why it wont work. It's not recieving the variable. Am i implementing the varable wrong with the $.each?
$('#autocomplete').autocomplete({
lookup: currencies,
onSelect: function (suggestion) {
var thehtml = '<strong>Item:</strong> ' + suggestion.value + ' <br> <strong>price:</strong> ' + suggestion.data + "<br>" + suggestion.divs;
var tableheader = ($("<thead>")
.append($("<tr>")
.append($("<th>Item</th><th>Qty</th><th>Price</th>")))
)
var selectValues = { "3": "2", "2": "1" , "1": "..."};
var select = $.each(selectValues, function(key, value){
$('.select').append($('<option>', {value: value}).text(value));
// <option value='volvo>Volvo</option>
});
var tr = "<tr><td>"+ suggestion.value + "</td><td><select class ='select'>" + select + "</select></td></tr>";
if($(".table").html().length <= 0)
{
$('.table').append($("<table>")).append(tableheader).append(tr);
}else{
if($(".table").html().length > 0){
$(".table").append(tr)
}
}
},
maxHeight:100,
width:600
});
thanks for your help

Why use object if you use only value?
if you realy don't need key juste create an array :
var selectValues = ["2", "1", "..."];
var value;
var select = selectValues.forEach(function(value){
$('.select').append($('<option>', {value: value}).text(value));
// <option value='volvo>Volvo</option>
});
// or if you want more compatibility
for (var i = 0, len = selectValue.length; i < len; i++) {
value = selectValue[i];
$('.select').append($('<option>', {value: value}).text(value));
});
Edit:
i make some mistake sorry.
first forEach will return nothing so it's can't work.
I test with your fidle. try this (replace by old for loop if you don't want to use map).
var select = selectValues.map(function(value){
return "<option value=" + value + ">" + value + "</option>";
// <option value='volvo>Volvo</option>
}).join('');
first you do not have to append from $('.select') because this dom not exist at this moment
and you can't concate an array in a string like this.

Getting a SelectList obejct from a ListBox and placing into an HTML Selection List

Say I have a ListBox populated with a name value pair SelectList(myUsers, "Key", "Value"):
#Html.ListBox("ListReviewers", (SelectList)ViewBag.ListOFReviewers, new { style = "width:120px;" })
I want to double click an option in this ListBox, and place it in a SelectionList like below:
<div class="selectedEmployees">
<select class="selectionList" multiple="multiple" name="AssignedReviewer" style="width:120px;">
<!--x.UserID, x.FirstName + " " + x.LastName) -->
<option value=""></option>
</select>
</div>
Once this collection is placed in the above, I want to store all the values in another SelectionList Collection for later use.
Here is the start of my jQuery code:
<script type="text/javascript">
$('#ListReviewers').dblclick(function (i, selected) {
//double click on this value of listbox of type SelectList(myUsers, "Key", "Value")
//store this value and text
var value = $(this).val;
//var empName = $(this).data[0];
var empName = $(selected).text();
alert(empName);
//append an option element <option value=""></option>
$('.selectionList').append('<option id="' + value + '">' + empName + '</option>');
});
I can get the value of the dblclicked collection object, but not the text of the collection object. Is there a better way to do this?

Try attaching your event to the option within the select itself. You can then use this to access it's properties.
$('#ListReviewers option').dblclick(function () {
var value = $(this).val();
var empName = $(this).text();
$('.selectionList').append('<option id="' + value + '">' + empName + '</option>');
});
Alternatively, you can use clone() and append() to move the option from one select to the other. This will save you having to worry about duplicate options being appended.
$('#ListReviewers option').dblclick(function () {
var $newOptions = $(this).clone(false);
$(this).remove();
$('.selectionList').append($newOption);
});