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! :)

Can i call another function inside the GetElement in Javascript

I am trying to call another function inside the getElement but it is not working everything when i change my selection. When i select Car, in the textbox my varxumb should populate. Any idea...
document.getElementById("mycall1").insertRow(-1).innerHTML = '<td><select id = "forcx" onchange="fillgap()"><option>Select</option><option>Force</option><option>Angle</option><option>Area</option></select></td>';
function fillgap() {
var xnumb = 20;
var forcxlist = document.getElementById("forcx");
if (forcxlist == "Force") {
document.getElementById("result1").value = xnumb;
}
}

I don't know how this "Force" value is coming to check.
you can try these solutions.
if (forcxlist == "Force")
instead use
var forcxlistText = forcxlist.options[forcxlist.selectedIndex].text;
if (forcxlistText == "Force")
or use value technique
<div id ="mycall1">
</div>
<div id ="result1">
</div>
<script>
document.getElementById("mycall1").innerHTML = '<td><select id = "forcx" onchange="fillgap(this.value)"><option value="1">Select</option><option value="2">Force</option><option value="3">Angle</option><option value="4">Area</option></select></td>';
function fillgap(value){
var xnumb = 20;
if (value == "2"){
document.getElementById("result1").innerHTML = xnumb;
}
}
</script>
or use
<div id ="mycall1">
</div>
<input type="text" id="result1" value=""/>
<script>
document.getElementById("mycall1").innerHTML = '<td><select id = "forcx"><option value="1">Select</option><option value="2">Force</option><option value="3">Angle</option><option value="4">Area</option></select></td>';
document.getElementById("forcx").onchange = function (){
var xnumb = 20;
var forcxlist = document.getElementById("forcx");
var forcxlistValue = forcxlist.options[forcxlist.selectedIndex].value;
if (forcxlistValue == "2"){
document.getElementById("result1").value = xnumb;
}
}
</script>

The forcxlist variable is an element object, returned by the document.getElementById method. Afterwards, you are checking if this element object is equal to "Force", which is a string (meaning the contents of your if block will never be executed). Did you mean to check if the contents of that object are equal to Force?
Instead of
if (forcxlist == "Force"){
use
if (forcxlist.innerHTML == "Force"){
I hope this helps!

Can't use innerHTML so i changed it to .value
document.getElementById("result1").value = xnumb;

There are a couple issues here.
First, you are expecting forcxlist to be a string, not an element, so you need to use .value to get the selected value of the dropdown.
Second, you should do your comparison with === not ==, as this ensures type equality as well, and is best practice.
I would also recommend building your select using HTML elements. It keeps things cleaner, is more readable, and is easier to maintain.
Since you are using the same id for the select, you would have to change the selector in your fillgap handler to var forcxlist = e.target.value;, this way the event will fire based on only the select that you are interacting with, regardless of how many rows you have in the table.
Updated code is below, and an updated working fiddle here. As per your comment about adding additional rows, the fiddle has this working as well.
<input type="button" value="Add Row" onclick="addDropDown()">
<table id="mycall1"></table>
<script>
function addDropDown() {
var tbl = document.getElementById("mycall1");
var newRow = tbl.insertRow(-1);
var newCell = newRow.insertCell(0);
newCell.appendChild(createDropDown("forcx", fillgap));
}
function createDropDown(id, onchange) {
var dd = document.createElement('select');
dd.id = id;
dd.onchange = onchange;
createOption("Select", dd);
createOption("Force", dd);
createOption("Angle", dd);
createOption("Area", dd);
return dd;
}
function createOption(text, dropdown) {
var opt = document.createElement("option");
opt.text = text;
dropdown.add(opt);
}
function fillgap() {
var xnumb = 20;
var forcxlist = e.target.value;
if (forcxlist === "Force") {
document.getElementById("result1").value = xnumb;
}
}
</script>
<input type="text" id="result1">

Dynamcially added class works on <td> but not on <tr>. Why?

The function simply injects new rows into an empty table when the function is called.
it would seem that since the <td> class gets assigned properly, that the <tr> would also get assigned... but it doesn't!
var newRow = document.createElement("tr");
for (data in dataArray)
{
var newName = document.createElement("td");
newName.className = classNames[data];
newName.innerHTML = dataArray[data];
newRow.appendChild(newName);
counter++;
}
document.getElementById("capturedData").appendChild(newRow);
var newRow2 = document.createElement("tr");
newRow2.class = "hiddenRow";
for (data in dataArray)
{
var newData = document.createElement("td");
var newDataField = document.createElement("input");
newDataField.type = "hidden";
newDataField.name = "name" + data;
newDataField.value = dataArray[data];
newData.class = classNames[data];
newData.value = dataArray[data];
newData.appendChild(newDataField);
newRow2.appendChild(newData);
}
which is really weird. All the newly added <td> elements have their classes assigned and they show up in the DOM. But the <tr> elements don't accept the class assignment and in the DOM they have no class.
Why is this? I've read about the purported asynchronicity of script execution, but surely this can't be the case, it would defeat the purpose, no?

DOM elements have no property class, because it is a reserved keyword. You are looking for className:
newRow2.className = "hiddenRow";
Same for the cell (newData). It works for your other cell because you are using className already:
newName.className = classNames[data];

Use only className, not class . There is no class-property in <TR>.

javascript button works in ie, not firefox or chrome

I'm writing a simple web page that displays a table. It the right column of the table I want to add a button in every row that says 'View'. I wrote a function that does this in ie by creating a button object and setting value = 'view' but in firefox and chrome the button displays with no text. Does anyone know why? Here is my code:
function addRow(id, sender, message){
var theTable = document.getElementById('messageTable');
var lastRow = theTable.rows.length;
var newRow = theTable.insertRow(lastRow);
newRow.id = id;
var cellLeft = newRow.insertCell(0);
var textNode = document.createTextNode(id);
cellLeft.appendChild(textNode);
var secondCell = newRow.insertCell(1);
var textNode2 = document.createTextNode(sender);
secondCell.appendChild(textNode2);
var messageCell = newRow.insertCell(2);
var messageNode = document.createTextNode(message);
messageCell.appendChild(messageNode);
var viewCell = newRow.insertCell(3);
var viewNode = document.createElement('button');
viewNode.value = 'View';
viewNode.onclick = function(){
alert('clicked: ' + id);
};
viewCell.appendChild(viewNode);
}

You have to do viewNode.innerHTML = 'View' since in FF button displays whatever is wrapped by the tag but not the value attribute

<button>s aren't self-closing like <input>s, and don't have a value attribute. You already have the solution in other parts of your code:
viewNode.appendChild(document.createTextNode('View'));
You also don't need to create variables for nodes that you're only using once. You can consolidate your code in a few places by using the above style.