Develop Reference

How to pass Object as parameter to a function onclick

I am facing some issues while trying to pass JSON object as a parameter to function!
but on that function, while consoling log the data I am getting [object:object].
Here is my code:
function buildTable(data) {
var table = document.getElementById("myTable");
table.innerHTML = "";
for (var i = 0; i < data.length; i++) {
var row = `<tr class="item-id-${data[i].id}"> <td>${data[i].name}</td> <td>${data[i].audio_muted}</td> <td>${data[i].video_muted}</td> <td><button id="audio_handle" class="btn btn-primary" onclick="handleMembers('${data[i]}')">Video</button></td>`;
table.innerHTML += row;
}
}
function handleMembers(data) {
console.log("data = >", data); //= [object:object]
}
The issue is when I am calling handle function from the button inside template literal string I m getting [object:object] as output
Where I am going wrong?

I fixed a few points in the following snippet and added some HTML and some sample data:
// some sample data for illustration:
const data=[{id:1,name:"Harry",audio_muted:1,video_muted:1},{id:2,name:"Ron",audio_muted:1,video_muted:0},{id:3,name:"Hermiony",audio_muted:0,video_muted:1},{id:4,name:"Ginny",audio_muted:0,video_muted:1}];
const tbl=document.getElementById("myTable");
tbl.innerHTML = data.map((itm,i)=>`<tr class="item-id-${itm.id}"> <td>${itm.name}</td> <td>${itm.audio_muted}</td> <td>${itm.video_muted}</td> <td><button data-id="${i}" class="btn btn-primary">Video</button></td>`).join("\n")
tbl.addEventListener("click",ev=>{
if (ev.target.tagName==="BUTTON")
console.log("data = >", data[ev.target.dataset.id]) ; //= [object:object]
})
<table id="myTable"></table>
As #Quentin already mentioned you should not include JavaScript code within a template string. This gets too complicated to read and to maintain. Instead I used a delegated event-handler on the table itself to listen for the click on the button elements. By doing all this there was no need anymore for the two named functions.
Another thing that comes to my mind is: Never use element.innerHTML += ... inside a for loop as this will potentially become really slow. It is generally better to assemble the whole HTML string in one go and then assign it to the innerHTML property.

I think it's the wrong approach to do that. You should try to create the element using the DOM api and add the eventListener to the selected element, something like:
function buildTable(data) {
const table = document.getElementById("myTable");
for(let d of data) {
const tr = document.createElement("tr");
const td1 = document.createElement("td");
td1.textContent = d.name;
const td2 = document.createElement("td");
td2.textContext = d.audio_muted;
const td3 = document.createElement("td");
td3.textContent = d.video_muted;
const tdButton = document.createElement("button");
tdButton.classList.add("btn", "btn-primary");
tdButton.addEventListener("click", () => handleMembers(d));
tr.appendChild(td1)
tr.appendChild(td2)
tr.appendChild(td3)
tr.appendChild(tdButton);
table.appendChild(tr)
}
}

JS Created buttons are not defined when accessed later

I have a script that makes a button in a table every 5 seconds.
I originally had the button made with the onclick attribute which called a function in the script. This however, gave me an error saying that the function didn't exist, and as from what I've seen on here, it has been answered but I don't know how I'd fix it in my situation. I switched it so that Javascript handles for the button click. I added attributes to the button tag to grab when the btnTeamListAction function is called. The console prints the following,
control.js:86 Uncaught TypeError: Cannot set property 'onclick' of null
at window.onload (control.js:86)
JS Snippets:
#button click handler
btnTeamListAction.onclick = function(){
var id = this.getAttribute("data-team-id");
var isRedo = this.getAttribute("data-is-redo");
teamListSelect(id,isRedo);
}
#the function that creates the buttons
function appendTeamTable(id,name,finished){
var finished_txt;
var action_content;
if(finished == 1){
finished_txt = "Yes";
action_content = '<button id="teams-list-action" data-team-id="'+id+'" data-is-redo="1">Retime</button>';
}
else {
finished_txt = "No";
action_content = '<button id="teams-list-action" data-team-id="'+id+'" data-is-redo="0">Time</button>';
}
var tr = document.createElement('tr');
tr.innerHTML ='<td>'+ id +'</td><td>'+ name +'</td><td>'+ finished_txt +'</td><td>'+ action_content +'</td>'
teamTable.appendChild(tr);
var btnTeamListAction = document.getElementById("teams-list-action");
btnTeamListAction.onclick = function(){
console.log("ActionClicked");
var id = this.getAttribute("data-team-id");
var isRedo = this.getAttribute("data-is-redo");
teamListSelect(id,isRedo);
}
}
I've tried browsing this form for this error and have found many related questions but not for this particular case with the button being created by JS itself.
Please ask if you need the full script or HTML, Thanks!

function appendTeamTable(id,name,finished){
var finished_txt;
var action_content= document.createElement("a");
var btn = document.createElement("button");
btn.setAttribute("id","teams-list-action");
btn.setAttribute("data-team-id",id);
if(finished == 1){
finished_txt = "Yes";
var t = document.createTextNode("Retime");
btn.setAttribute("data-is-redo","1");
}
else {
finished_txt = "No";
var t = document.createTextNode("Time");
btn.setAttribute("data-is-redo","0");
}
btn.appendChild(t);
btn.addEventListener("click",function(){
var id = this.getAttribute("data-team-id");
var isRedo = this.getAttribute("data-is-redo");
teamListSelect(id,isRedo);
});
action_content.appendChild(btn);
var tr = document.createElement('tr');
var td = document.createElement('td');
td.appendChild(action_content);
tr.innerHTML ='<td>'+ id +'</td><td>'+ name +'</td><td>'+ finished_txt +'</td>'
tr.appendChild(td);
teamTable.appendChild(tr);}

I looked at the post here and took the idea from the second answer and put a event handler on the table itself instead of the buttons individually. It's works like a charm now. Thanks all three of you for attempting to look through my seriously messed up code! :)

Accessing row element of table in Javascript

This is my first attempt in Javascript, so may be this is fairly easy question.
I need to access row element of a table, each row contains checkbox and two other column. If checkbox is checked, i need to get the id of checkbox.
I made following attempt but element_table.rows returns undefined, therefore i could not proceed. I debugged using Inspect element tool of eclipse and found element_table contains the rows.
Please suggest where I am making a mistake.
Javascript code:
function myfunction3(){
var element_table = document.getElementsByName('collection');
var element_tableRows = element_table.rows;
var selectedTr = new Array();
var data = "";
for(var i =0 ; element_tableRows.length;i++)
{
var checkerbox = element_tableRows[i].getElementsByName('checkmark');
if(checkerbox.checked){
selectedTr[selectedTr.length] = element_tableRows[i].getAttribute("name");
data = data + element_tableRows[i].getAttribute("name");
}
}
var element_paragraph = document.getElementsByName('description');
element_paragraph.innerHTML = data;
}
html code:
<table name="collection" border="1px">
<tr name="1">
<td><input type="checkbox" name="checkmark"></td>
<td>Tum hi ho</td>
<td>Arjit singh</td>
</tr>
<tr name="2">
<td><input type="checkbox" name="checkmark"></td>
<td>Manjha</td>
<td>Somesh</td>
</tr>
<tr name="3">
<td><input type="checkbox" name="checkmark"></td>
<td>Ranjhana</td>
<td>A.R Rehman</td>
</tr>
</table>
<input type="button" value="Check" onclick="myfunction3()">

here's a working version
function myfunction3(){
var element_table = document.getElementsByName('collection');
var element_tableRows = element_table[0].rows;
var selectedTr = new Array();
var data = "";
for(var i =0 ; i < element_tableRows.length;i++)
{
var checkerbox = element_tableRows[i].cells[0].firstChild;
if(checkerbox.checked){
//selectedTr[selectedTr.length] = element_tableRows[i].getAttribute("name"); //not sure what you want with this
data = data + element_tableRows[i].getAttribute("name");
}
}
var element_paragraph = document.getElementsByName('description');
element_paragraph.innerHTML = data;
alert(data);
}
http://jsfiddle.net/eZmwy/
jsfiddle for your example, your problem is mainly at when you getElementsByName you need to specify the index, also not that not all getElement methods are available in the table
i would also suggest you learn jQuery, this makes life easier, also not sure why you want to display the data as 1,2,3 the name on the tr... seems pretty strange to me

Actually this line
var element_table = document.getElementsByName('collection');
will return collection of elements. If you are sure that you have exactly one table with the specified name, try this approach:
var element_table = document.getElementsByName('collection')[0];

actually if you are using jQuery (very recommanded )
you can do something like
var idsArray = [];
$("[name=collection] tr td [type=checkbox]:checked").parent().each(function() {
idsArray .push($(this).attr('name'))
});
this answer related only to jQuery use (which is same as javascript only more compiled.)

How to delete a created element in JavaScript?

Hello I have a piece of code that allows me to add an author.
I have a problem, I can't seem to delete the created node in my table
This is the worst frustration in my life. I could not seem to delete it.
I also have notice that every time I inspected the element I could not see the
new created element from the source. But when I view it on firebug I can actually see it there.
Adding an input element and appending it on the table works fine for me.
I am just very new to JavaScript and to this web thingy and deleting a CREATED ELEMENT via .createElement is where I am stuck at.
here is my code
<script>
var ctr = 1;
function showTextBox()
{
// is the table row I wanted to add the element before
var target = document.getElementById('bef');
var tblr = document.createElement('tr');
var tbld1 = document.createElement('td');
var tbld2 = document.createElement('td');
var tblin = document.createElement('input');
tblin.name = 'Author' + ctr;
tblin.id = 'Author' + ctr;
tblin.placeholder = 'add another author';
tbld1.appendChild( document.createTextNode('Author' + ctr ) );
tbld2.appendChild( tblin );
tblr.appendChild( tbld1 );
tblr.appendChild( tbld2 );
target.parentNode.insertBefore( tblr , target );
ctr++;
}
function hideTextBox()
{
var name = 'Author'+ctr;
var pTarget = document.getElementById('tbhold');
var cTarget = document.getElementById( name );
alert( cTarget ); // this one return null? Why? I have created id="Author1"
// viewing this code on source make the created elem to not appear
}
</script>
Am I doing something wrong? I really need help. This is for my project at school.
Is there any way I could delete it. I created that node and I want it to be deleted when I click something.
Also I prefer to stay with JS not with JQuery or other JStuff and I am disregarding compatibility for now because this is just a sample in my dummy form. I will deal on that later.
EDIT
In case you need the actual form here it is
<form enctype="multipart/form-data" action="process/" method="POST" />
<h3>Book Upload</h3>
<table border="2" id='tbhold'>
<tr>
<td>Title</td>
<td><input type="text" id="book_title" name="book_title" /></td>
</tr>
<tr>
<td>Author</td>
<td><input type="text" id="book_author" name="book_author" /></td>
</tr>
<tr id="bef">
<td colspan="2">
add author
remove
</td>
</tr>
</table>
</form>
Thank you very much!

Try this function:
function removeElements(elements){
for(var i = 0; i < elements.length; i++){
elements[i].parentNode.removeChild(elements[i]);
}
}
Then you can do this:
removeElements(document.querySelectorAll('#tbhold tr'));

function hideTextBox(){
var name = "Author" + (ctr - 1);
var pTarget = document.getElementById('tbhold');
var cTarget = document.getElementById(name);
var tr = cTarget.parentNode.parentNode;
tr.parentNode.removeChild(tr);
ctr = ctr - 1;
}
Here is a demo

every time I inspected the element I could not see the new created element from the source. But when I view it on firebug I can actually see it there.
If you change the DOM, you of course do not change the HTML source markup. Only the DOM inspector will show you the changes.
var name = 'Author'+ctr;
var cTarget = document.getElementById( name );
alert( cTarget ); // this one return null? Why? I have created id="Author1"
Yes, you created it using your showTextBox function. But that did also increment the ctr to 2, so that you now are looking for Author2 which obviously does not exist. So put a ctr--; before it and it should work.

Cannot call method appendChild of null

It occurs in this:
for(var i = 0; i<phoneNums.length; i++)
{
var lines = document.createElement('tr');
var number = document.createElement('td');
number.innerHTML = phoneNums[i];
var minutes = document.createElement('td');
minutes.innerHTML = minutesUsed[i];
var plan = document.createElement('td');
plan.innerHTML = plans[i];
var charges = document.createElement('td');
charges.innerHTML = charge[i];
document.getElementById('theTable').appendChild(lines);
lines.appendChild(number);
lines.appendChild(minutes);
lines.appendChild(plan);
lines.appendChild(charges);
}
Specifically at:
document.getElementById('theTable').appendChild(lines);
<table id = 'theTable'>
</table>
<script type = 'text/javascript'>
populateTable();
</script>
I'm trying to create a function that adds tr and td and the values to a table.

You probably are running this script before "theTable" exists in your document. Make sure that this script occurs below your table with id="theTable", or that it is run in an event handler that occurs after the table exists.

This means that you do not have an element in your DOM with an id of "theTable". Somewhere in your html you should have something like:
<table id="theTable">...
Alternatively, as others have also mentioned, this element may not have been loaded into the DOM before your script executes.