Adding button that removes object from array inside a table - javascript

Created a form and empty table, trough DOM i should create a new object from class Movie and insert it in empty table with a button to remove it.
Don't know how i would create the button with a function to remove the movies[i] in the table. Sorry I am still learning and don't know how to express my problems.
window.onload = function(){
let frmMovies = document.getElementById("frmMovies");
let txtTitle = document.getElementById("txtTitle");
let txtYear = document.getElementById("txtYear");
let txtGender = document.getElementById("txtGender");
frmMovies.addEventListener("submit", function (event) {
let newMovie = new Movies(txtTitle.value, txtYear.value, txtGender.value);
movies.push(newMovie);
refreshTable();
/*let btn = document.getElementsByClassName("btn");
btn.addEventListener("click", function (event) {
movies.splice(x, 1);
event.preventDefault();
})*/
event.preventDefault();
})
}
function refreshTable() {
let movieTable = document.getElementById("movieTable");
let txt = "";
txt = "<tr><th>TÍTULO</th><th>ANO</th><th>GÉNERO</th><th>!</th></tr>";
for(let i = 0 ; i < movies.length; i++){
txt += "<tr>";
txt += "<td>" + movies[i].title + "</td>";
txt += "<td>" + movies[i].year + "</td>";
txt += "<td>" + movies[i].gender + "</td>";
txt += "<td>" + "<button class='btn'>" + "Remove" + "</button>" + "</td>";
txt += "</tr>";
}
movieTable.innerHTML = txt;
}

You could add an onclick attribute to your Remove buttons when you build it. Upon clicking on the button, it will call a function passing current button element i.e. this.
let movies = [];
// etc
function refreshTable() {
let movieTable = document.getElementById("movieTable");
let txt = "";
txt = "<tr><th>TÍTULO</th><th>ANO</th><th>GÉNERO</th><th>!</th></tr>";
for(let i = 0 ; i < movies.length; i++){
txt += "<tr>";
txt += "<td>" + movies[i].title + "</td>";
txt += "<td>" + movies[i].year + "</td>";
txt += "<td>" + movies[i].gender + "</td>";
txt += "<td>" + "<button type='button' class='btn' onclick='deleteRow(this)'>" + "Remove" + "</button>" + "</td>";
txt += "</tr>";
}
movieTable.innerHTML = txt;
}
Create your new function which will delete the current row using .removeChild().
function deleteRow(button) {
let row = button.parentElement.parentElement;
document.getElementById("movieTable").removeChild(row);
}
This is untested of course but you could do something like this.

Event Delegation is the most efficient way of using one element to listen for an event for multiple child/descendant elements. Simply find an ancestor (tbody) element that the group of target elements (buttons) have in common.
Demo
// Reference the <tbody> by its tagName
var tbody = document.querySelector('tbody');
// Register the click event on <tbody> calls removeRow when clicked
tbody.addEventListener('click', removeRow, false);
// Pass through the Event Object
function removeRow(event) {
/* Event Object property Event.target always knows which
|| element was actually clicked. Use event.target to compare
|| or assert a true/false check in order to target the rest of
|| the DOM in reference to event.target.
|| Find the closest <tr> from event.target
|| `this` is the function owner <tbody> which removes the <tr>
*/
if (event.target.className === 'btn') {
var row = event.target.closest('tr');
this.removeChild(row);
}
return false;
}
<table>
<tbody>
<tr>
<td>Reservoir Dogs</td>
<td>1992</td>
<td>Male?</td>
<td><button class='btn'>Remove</button></td>
</tr>
<tr>
<td>The Usual Suspects</td>
<td>1995</td>
<td>Male?</td>
<td><button class='btn'>Remove</button></td>
</tr>
<tr>
<td>Pulp Fiction</td>
<td>1994</td>
<td>Male?</td>
<td><button class='btn'>Remove</button></td>
</tr>
<tr>
<td>Sin City</td>
<td>2005</td>
<td>Male?</td>
<td><button class='btn'>Remove</button></td>
</tr>
<tr>
<td>Old Boy</td>
<td>2003</td>
<td>Male?</td>
<td><button class='btn'>Remove</button></td>
</tr>
</tbody>
</table>

Since you're new to this, I would recommend really focusing on understanding the difference between an actual DOM element and the HTML tags that are used to create them.
The DOM is the actual mechanism that determines what is displayed on the page. HTML is just a way of serializing a DOM into text, so you can easily send it over networks to other computers. A web browser parses HTML and recreates the DOM on the client's computer.
The DOM consists of JavaScript objects that you can manipulate with Javascript. When you set movieTable.innerHTML, what you're doing is telling the browser: to do the following:
Parse the assigned string as HTML.
Delete all of the children of movieTable.
Add the new DOM elements parsed from the assigned string as children of movieTable.
This is wasteful because you're recreating the entire table every time you do it, even though you may only be adding or removing a single element. It also can be frustrating to maintain, since JS does not play well with long string literals. This is one of the reasons why stuff like this is often handled by templating libraries.
I'll keep it simple though, and show you how you can do this with just the standard DOM methods:
let frmMovies = document.getElementById("frmMovies");
let txtTitle = document.getElementById("txtTitle");
let txtYear = document.getElementById("txtYear");
let txtGender = document.getElementById("txtGender");
// You don't need to keep getting this every time.
// Just get it once and reuse the reference.
let movieTable = document.getElementById("movieTable");
frmMovies.addEventListener("submit", function (event) {
// You can do this anytime, as long as you do it before your
// handler returns. I usually do it right away.
event.preventDefault();
// First, let's create a new table row.
let movieRow = document.createElement("tr");
// Create the title cell.
let titleCell = document.createElement("td");
titleCell.innerText = txtTitle.value;
// Create the year cell.
let yearCell = document.createElement("td");
yearCell.innerText = txtYear.value;
// Create the gender cell.
let genderCell = document.createElement("td");
genderCell.innerText = txtGender.value;
// Create the remove button and a cell to put it in.
let buttonCell = document.createElement("td");
let removeButton = document.createElement("button");
removeButton.innerText = 'Remove';
// Attach the click handler for the remove button.
removeButton.addEventListener("click", function() {
// This handler will form a *closure*, which will store the
// reference to the movieRow, enabling you remove it by simply
// calling `remove` on it.
movieRow.remove();
});
// Now, let's put it all together:
// Add the remove button to its cell.
buttonCell.appendChild(removeButton);
// Add the cells to the table row.
movieRow.appendChild(titleCell);
movieRow.appendChild(yearCell);
movieRow.appendChild(genderCell);
movieRow.appendChild(buttonCell);
// Add the table row to the table.
movieTable.appendChild(movieRow)
});
MDN has some pretty solid documentation of standard HTML DOM that you'll probably want to check out:
https://developer.mozilla.org/en-US/docs/Web/API/Document_Object_Model

Related

Get value of first <td> element in same row as input button

I am trying to get the text from the first td tag from each row by using the input button as shown below:
for(var i in obj.questions){
question += '<tr class="row">';
question += "<td>"+ obj.questions[i].question+"</td>";
question += '<td><input type="button" class="question" value="Add question" onclick="addQuestion()"></td>';
question += "</tr>";
document.getElementById("t01").innerHTML = question;
}
The id=t01 is for the table tag. Here is the js that I tried working on but is not working:
var question;
$('.question').click(function() {
question = $(this).parent().find('td:first-child').text();
});
You have to iterate through each row like below
$('.question').click(function () {
$('#t01 .row').each(function () {
console.log($(this).find("td:first-child").text());
});
});
Also I would suggest to write html use jQuery instead of javascript instead of document.getElementById("t01").innerHTML
$('#t01').html(question);
Also your implementation of creating rows dynamically have one problem , you will get only one row every time. You can change your code like below
var question = "";
for (var i in questions) {
question += '<tr class="row">';
question += "<td>" + questions[i].question + "</td>";
question += '<td><input type="button" class="question" value="Add question" onclick="addQuestion()"></td>';
question += "</tr>";
}
$('#t01').html(question);
I have created a running sample for you
https://stackblitz.com/edit/jquery-n4spxc?file=index.js
You may need to use .live() to achieve this, depending on the order of your event binding and HTML generation. Also, consider revising your click event logic so that you iterate over all rows of the table to access the text of "first cell" for each table row:
// When the .question input is added to the DOM, this event logic will
// be bound to the input element automatically
$(document).live('.question', 'click', function() {
var question;
// Iterate over each row of the table
$('#t01 .row').forEach(function() {
// For each row, extract the text from first row cell
var row = $(this);
var firstCell = row.find('td:first-child');
var firstCellText = firstCell.text();
// Not sure how you want to use the data, this shows
// how to construct a comma separated string of text
// from all first row cells
question += firstCellText + ',';
});
// Print result to console
console.log(question);
});

Confusing behaviour on passing object as parameter to a method called from Table created in Javascript

I'm have a table with buttons in each row. On every button click I want to pass that row's data to a method. I've done the following
HTML
<body>
<div>
<button onclick="load()" >Click</button>
<table id="roleTable">
<thead>
<tr>
<td>EnterpriseId</td>
<td>Role</td>
<td>UserId</td>
</tr>
</thead>
<tbody>
</tbody>
</table>
</div>
</body>
Javascript
function load() {
var data = JSON.parse(sessionStorage.getItem("loginInfo"));
var html = "";
for (var i = 0; i < data.length; i++) {
html += "<tr><td>" + data[i].ENTERPRISE_ID + "</td>";
html += "<td><button type='button' onclick='loadSegment(data[" + i + "])'>...</button></td>";
html += "<td>" + data[i].USER_ID + "</td></tr>";
}
document.getElementById('roleTable').getElementsByTagName("TBODY")[0].innerHTML = html;
}
function loadSegment(o) {
alert('reading obj');
alert(JSON.stringify(o));
}
The problem is when I click on the button with given code, nothing happens.
But if I move the code of load() function out, the loadSegment method gets called and I'm able to use the object as I want.
Working JS
//function load() { // Commented the function call
var data = JSON.parse(sessionStorage.getItem("loginInfo"));
var html = "";
for (var i = 0; i < data.length; i++) {
html += "<tr><td>" + data[i].ENTERPRISE_ID + "</td>";
html += "<td><button type='button' onclick='loadSegment(data[" + i + "])'>...</button></td>";
html += "<td>" + data[i].USER_ID + "</td></tr>";
}
document.getElementById('roleTable').getElementsByTagName("TBODY")[0].innerHTML = html;
//}
function loadSegment(o) {
alert('reading obj');
alert(JSON.stringify(o));
}
I don't understand why through the second code the method is reachable but not from the first code. If I don't pass object as parameter in the first code then it is able to reach to the loadSegment() function.
Can anybody please help me understand what is the exact issue her. And how can I achieve the function call from the first JS code.
Update
JSON string
[{"USER_ID":"UID00007","ENTERPRISE_ID":"admin1","ROLE":"ADMIN"},
{"USER_ID":"UID00008","ENTERPRISE_ID":"admin2","ROLE":"TESTER"},
{"USER_ID":"UID00009","ENTERPRISE_ID":"admin3","ROLE":"REVIEWER"},
{"USER_ID":"UID00010","ENTERPRISE_ID":"admin4","ROLE":"PMO"},
{"USER_ID":"UID00011","ENTERPRISE_ID":"admin5","ROLE":"MANAGER"},
{"USER_ID":"UID00012","ENTERPRISE_ID":"admin6","ROLE":"DEVELOPER"},
{"USER_ID":"UID00013","ENTERPRISE_ID":"admin7","ROLE":"DBA"}]
In the first example, the data variable exists only within the scope of the load function:
function load() {
var data = JSON.parse(sessionStorage.getItem("loginInfo"));
//...
}
And then you try to reference it outside of that function:
onclick='loadSegment(data[0])'
It doesn't exist at this point, so you can't reference it. By contrast, in the second example you create the data variable in global scope, so it exists on the window object and can be referenced anywhere.
To encapsulate the data variable within that function, you'll need to supply the HTML you're creating with all of the information it needs to call the loadSegment function, not just an index reference. Maybe serialize the whole value into the function call? Maybe put values on data-* attributes? Maybe move all the code into the function except the data variable and keep that on window scope? You have options, depending on what you're trying to achieve overall.
Side note: You might not want to create something called load on the window object (or any other DOM object). If not actual problems, that could cause confusion with other code.
Changing the functionName will help
function loadfun()
{
var data = JSON.parse(sessionStorage.getItem("loginInfo"));
var html = "";
for (var i = 0; i < data.length; i++) {
html += "<tr><td>" + data[i].ENTERPRISE_ID + "</td>";
html += "<td><button type='button' onclick='loadSegment(data[" + i + "])'>...</button></td>";
html += "<td>" + data[i].USER_ID + "</td></tr>";
}
document.getElementById('roleTable').getElementsByTagName("TBODY")[0].innerHTML = html;
}
function loadSegment(o) {
alert('reading obj');
alert(JSON.stringify(o));
}

How can I update the attributes of an HTML element inside a table cell?

I have a table which looks essentially like this
<!DOCTYPE html>
<html lang="en">
<body>
<table class="ui table" id="items">
<tbody>
<tr data-toggle="fieldset-entry">
<td><input id="items-0-quantity" name="items-0-quantity" type="text" value=""></td>
<td><input id="items-0-description" name="items-0-description" type="text" value=""></td>
</tr>
</body>
</html>
Using javascript, I'd like to have a button which adds a new row to the table, and I'd like the inputs in that new row to have id="items-1-xxx", and name="items-1-xxx, i.e. where there's a 0 in the original row I'd like a 1 in the new row.
I can make a new table row by cloning the old one, but I have not figured out how to modify the name and id attributes of the input.
Here's a sketch of what I've tried:
function cloneRow() {
var table = document.getElementById("items");
var original_row = table.rows[table.rows.length - 1];
var new_row = original_row.cloneNode(true);
// We have a new row and now we need to modify it as
// described in the question. The only way I've found
// is to grab the inner HTML:
var cell_contents = original_row.cells[0].innerHTML;
// Now we could do a bunch of string parsing and manipulations
// to increment the 0 to a 1 and stuff the modified HTML into
// new_row, but it seems there must be a better way.
// Finally insert the new row into the table.
original_row.parentNode.insertBefore(new_row, original_row.nextSibling);
}
What is the right way to update the input elements' id and name?
You could just build a new <td> and assign document.querySelectorAll('#items tr').length as the x in items-x-...:
function addItem() {
var items = document.querySelector('#items')
, itemcount = items.querySelectorAll('tr').length
, newitemQuantityText = 'items-' + itemcount + '-quantity'
, newitemDescriptionText = 'items-' + itemcount + '-description'
, newitem = document.createElement('tr')
, newitemQuantity = document.createElement('td')
, newitemDescription = document.createElement('td')
, newitemQuantityInput = document.createElement('input')
, newitemDescriptionInput = document.createElement('input');
newitemQuantityInput.id = newitemQuantityText;
newitemQuantityInput.name = newitemQuantityText;
newitemQuantity.appendChild(newitemQuantityInput);
newitemDescriptionInput.id = newitemDescriptionText;
newitemDescriptionInput.name = newitemDescriptionText;
newitemDescription.appendChild(newitemDescriptionInput);
newitem.appendChild(newitemQuantity);
newitem.appendChild(newitemDescription);
document.querySelector('#items').appendChild(newitem);
}
document.querySelector('#add').addEventListener('click', addItem);
<button id="add">add item</button>
<table id="items"></table>
However using good old innerHTML reads way better:
function addItem() {
var items = document.querySelector('#items')
, itemcount = items.querySelectorAll('tr').length;
items.innerHTML += '<tr><td>' +
'<input id="item-' + itemcount + '-quantity" name="item-' + itemcount + '-quantity">' +
'</td><td>' +
'<input id="item-' + itemcount + '-description" name="item-' + itemcount + '-description">' +
'</td></tr>';
}
document.querySelector('#add').addEventListener('click', addItem);
<button id="add">add item</button>
<table id="items">
</table>
You can separately reconstruct the node itself by using
createAttribute()
createElement()
Fiddle: http://jsfiddle.net/ztb9gq3d/1/
This is not the data oriented approach the question asks for, but a reasonably simple solution is
numRows = table.rows.length;
// Use a regexp so we can replace all instances of the number
// corresponding to what is currently the last table row.
var re = new RegExp((numRows - 1).toString(), "g")
for (var i = 0; i <= originalRow.cells.length - 1; i++) {
var originalHTML = originalRow.cells[i].innerHTML;
var newHTML = originalHTML.replace(re, numRows.toString());
newRow.cells[i].innerHTML = newHTML;
}
Obviously this only works if the number we replace doesn't exist elsewhere in the HTML string, so this is not a particularly good solution.
However, we could use a more complex regexp.
This solution does have the advantage that we don't need to hard-code anything except the parts we want to replace into the regexp.
Therefore, if the HTML in the table were to acquire additional parts in future development this solution will still work, up to the quality of the regexp as already mentioned.

Displaying table using Javascript breaks inside for loop

I have a code to populate a table using Javascript as:
var myResponse = document.getElementById("jsonPlaceHolder");
myResponse.innerHTML += "<table border=1> <tr> <td> User Id </td> <td> Question </td> <td> Link Question </td> </tr>";
for (var i = 0; i < 25; i++) {
myResponse.innerHTML += "<tr>"
myResponse.innerHTML += "<td>" + jsonObj[i]["user_id"] + "</td>";
myResponse.innerHTML += "<td>" + jsonObj[i]["text"] + "</td>";
myResponse.innerHTML += "</tr>"
}
myResponse.innerHTML += "</table>";
Problem with this code is when I run this table is not continued inside for loop. If I add
myResponse.innerHTML += "<table><tr>"
inside my for loop, table is created. Isn't this bit odd?,
since i am using += to add to current innerHTML of the DOM element.
One of the most misunderstood thing about innerHTML stems from the way the API is designed. It overloads the + and = operators to perform DOM insertion. This tricks programmers into thinking that it is merely doing string operations when in fact innerHTML behaves more like a function rather than a variable. It would be less confusing to people if innerHTML was designed like this:
element.innerHTML('some html here');
unfortunately it's too late to change the API so we must instead understand that it is really an API instead of merely an attribute/variable.
When you modify innerHTML it triggers a call to the browser's HTML compiler. It's the same compiler that compiles your html file/document. There's nothing special about the HTML compiler that innerHTML calls. Therefore, whatever you can do to a html file you can pass to innerHTML (the one exception being that embedded javascript don't get executed - probably for security reasons).
This makes sense from the point of view of a browser developer. Why include two separate HTML compilers in the browser? Especially considering the fact that HTML compilers are huge, complex beasts.
The down side to this is that incomplete HTML will be handled the same way it is handled for html documents. In the case of elements not inside a table most browsers will simply strip it away (as you've observed for yourself). That is essentially what you're trying to do - create invalid/incomplete HTML.
The solution is to provide innerHTML with complete HTML:
var htmlString = "<table border=1> <tr> <td> User Id </td> <td> Question </td> <td> Link Question </td> </tr>";
for (var i = 0; i < 25; i++) {
htmlString += "<tr>"
htmlString += "<td>" + jsonObj[i]["user_id"] + "</td>";
htmlString += "<td>" + jsonObj[i]["text"] + "</td>";
htmlString += "</tr>"
}
htmlString += "</table>"
myResponse.innerHTML += htmlString;
Use the DOM API to manipulate the DOM:
var myResponse = document.getElementById("jsonPlaceHolder");
var table = document.createElement('table'),
headings = ["User ID", "Question", "Link Question"];
table.style.border = "1";
var r = table.insertRow(-1);
for (var i = 0; i < 3; i++) {
(function(){
return r.insertCell(-1);
})().innerHTML = heading[i];
}
for (var i = 0; i < 25; i++) {
r = table.insertRow(-1);
var userid = r.insertCell(-1),
text = r.insertCell(-1);
userid.innerHTML = jsonObj[i]["user_id"];
text.innerHTML = jsonObj[i]["text"];
}
myResponse.appendChild(table);

Create an editable HTML table

I'm trying to follow the prof's example of creating an editable table on double clicking an entry in a HTML table. So my data method looks like this:
function formatData(message) {
var str = "<table border=1>";
for (var i = 0; i < message.length; i++) {
str += "<tr>" + "<td class='editable'>" + message[i].id + "</td>" +
"<td>" + message[i].name + "</td>" +
"<td class='editable'>" + message[i].url + "</td>" +
"<td class='editable'>" + message[i].desc + "</td>" +
"<td>" + "<a href='#' onclick='deleteRequest(this); return false' id='" + message[i].id + "'>delete</a>" + "</td>" +
" + "</td>" + "</tr>";
}
str += "</table>";
return str;
}
I bind a function edit() to the tags whose attributes are of class 'editable.' Then my edit function does:
function edit(elm) {
/* check to see if we are already editing */
if (elm.firstChild.tagName && elm.firstChild.tagName.toUpperCase() == "INPUT")
return;
/* save original content */
var orig = elm.innerHTML;
/* create edit field */
var input = document.createElement("input");
input.type = "text";
input.value = elm.innerHTML;
input.size = 20;
/* convert content to editable */
elm.innerHTML = '';
elm.appendChild(input);
/* position cursor and focus */
if (input.selectionStart)
input.selectionStart = input.selectionEnd = 0;
else
{
var range = input.createTextRange();
range.move("character", 0);
range.select();
}
input.focus();
/* set save trigger callback */
input.onblur = function(){save(elm, input,orig);};
}
I'm confused on how I would save the information and pass it to the web server to update. I need the id, url, and desc to update the web server. Since they double click on a table entry, that just gives me the element at that value, but I don't have the id. Do I change two lines in my formatData to:
"<td class='editable' id='" + message[i].id + "'>" + message[i].url + "</td>" +
"<td class='editable' id='" + message[i].id +"'>" + message[i].desc + "</td>" +
So that way I can ask the webserver for the url and desc with that id value? That seems like a bad way to do it since now two have the same id, but I'm not sure since I'm relatively new to AJAX, HTML, Javascript. Thanks.
Eh, I'll push a bit of help your way.
Basically, from what I gather you're binding a function to each td tag with editable. Well, you can determine the id inside that function.
B/c you can select the parentNode of the current node being edited, and then select the firstChild of that parentNode, so parentNode.firstChild which should be the first td, since remember on each row each of your td's will have a single parent tr. Then you select the firstChild of that td node, which is the text node it contains, and then grab its value, the id. So parentNode.firstChild.firstChild.nodeValue
This might not follow exactly with your code, as you only show parts of it... but this is the gist of the idea. Basically selecting nodes through the DOM and pulling the right one based on the current context.
I'd suggest playing around with it till you get it.
Here's a little bit of sample code for you to think about if you get stuck still. It's meant to be brief.
Basically, each middle column is tagged with the test function on the onfocus event (clicking inside the input). So it's on the input itself, and it pulls the parentNode td, then the next parentNode tr, then the firstChild of tr which is the first td then the firstChild of the first td which is the input on that row, then finally that input's value attribute.
<script>
function test(elem) {
alert( elem.parentNode.parentNode.firstChild.firstChild.value );
}
</script>
<table>
<tr><td><input value="1"/></td><td><input value="stuff" onfocus="test(this)"/></td><td>other stuff</td></tr>
<tr><td><input value="2"/></td><td><input value="stuff3" onfocus="test(this)"/></td><td>other stuff</td></tr>
<tr><td><input value="3"/></td><td><input value="stuff2" onfocus="test(this)"/></td><td>other stuff</td></tr>
</table>

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