Develop Reference

Trouble adding element with text to DOM tree

I created an unordered list of elements and I'm trying to add a new element using DOM manipulation.
var newEl = document.create Element('li');
var newText = document.createTextNode('Hawaii');
var newEl = newEl.appendChild(newText);
document.getElementsByTagName('ul')[0].appendChild(newEl);
The element was added to the ul element but it was not added as an li element, so my new text doesn't have any bulleting.

This line
var newEl = newEl.appendChild(newText);
Change to
newEl.appendChild(newText);
When you reassign it its not the li anymore (this is not JQ)

.appendChild returns the appended element. In this case your newEl will be a text node after this assignment.
var newEl = newEl.appendChild(newText);
You should remove the assignment and it is fine.

avoid the reassignment to newEl.
var newEl = document.createElement('LI');
var newText = document.createTextNode('Hawaii');
newEl.appendChild(newText);
document.getElementsByTagName('ul')[0].appendChild(newEl);

You can try this.
Set an id to your ul element and append your new li in ul tag
var node = document.createElement("li");
var textnode = document.createTextNode("Hawaii");
node.appendChild(textnode);
document.getElementById("myList").appendChild(node);
<ul id="myList">
<li>Item 1</li>
<li>Itm 2</li>
</ul>

How to appendChild an UL to a SPAN?

So, if we're going to append a LI to UL we should do this:
var list = document.createElement('li');
var ulist = document.createElement('ul');
ulist.appendChild(list);
what if I create a span, should I do this?
var list = document.createElement('li');
var ulist = document.createElement('ul);
var span = document.createElement('span');
span.appendChild(ulist);
ulist.appendChild(list);

That's the sort of thing you'd do, yes (other than the typo — missing closing '), except span elements cannot contain ul elements. The content model of span is phrasing content, but ul can only be used where flow content is expected.

You are missing a quote after ul, but your code is correct.
In your latter code, you are appending a <li> to a <ul> and this same <ul> to a <span>. You may want to append all this to the body to make them appear. See example below:
const list = document.createElement('li');
const ulist = document.createElement('ul');
const span = document.createElement('span');
span.appendChild(ulist);
ulist.appendChild(list);
document.body.appendChild(span);

JavaScript Not able to set focus to first li element within ul

I have below code:
<ul id='someId'>
<li class='someClass'>
</li>
</ul>
I want to set focus on first li element within ul based on some condition.
My first attempt is like this:
var ul = document.getElementById('someId');
var child = ul.childNodes[0];
child.focus();
My second attempt is like this :
var y = document.getElementsByClassName('someClass');
var aNode = y[0];
aNode.focus();
But none of the above works
Any ideas?

The problem is that you can't focus a non input element without setting tabIndex.
<li tabIndex="-1">...</li>
You can Try this fiddle: jsfiddle

An 'li' can't have focus, however an 'input' can, so you write yourself the following script:
function installLI(obj){
var ul = document.createElement('ul');
obj.appendChild(ul);
var li = document.createElement('li');
var txt = document.createElement('input');
li.appendChild(txt);
ul.appendChild(li);
txt.focus();
li.removeChild(txt);
}
Where 'obj' is the object (like an editable div) that you're appending your list to.

how to add new <li> to <ul> onclick with javascript

How do I add a list element to an existing ul using a function from an onclick? I need it to add to this type of list ...
<ul id="list">
<li id="element1">One</li>
<li id="element2">Two</li>
<li id="element3">Three</li>
</ul>
... another list item with the id "element4" and text "Four" under that. I tried this function but it doesn't work...
function function1() {
var ul = document.getElementById("list");
var li = document.createElement("li");
li.appendChild(document.createTextNode("Element 4"));
}
I don't know JQuery so Javascript only please. Thank you!!

You have not appended your li as a child to your ul element
Try this
function function1() {
var ul = document.getElementById("list");
var li = document.createElement("li");
li.appendChild(document.createTextNode("Four"));
ul.appendChild(li);
}
If you need to set the id , you can do so by
li.setAttribute("id", "element4");
Which turns the function into
function function1() {
var ul = document.getElementById("list");
var li = document.createElement("li");
li.appendChild(document.createTextNode("Four"));
li.setAttribute("id", "element4"); // added line
ul.appendChild(li);
alert(li.id);
}

You were almost there:
You just need to append the li to ul and voila!
So just add
ul.appendChild(li);
to the end of your function so the end function will be like this:
function function1() {
var ul = document.getElementById("list");
var li = document.createElement("li");
li.appendChild(document.createTextNode("Element 4"));
ul.appendChild(li);
}

First you have to create a li(with id and value as you required) then add it to your ul.
Javascript ::
addAnother = function() {
var ul = document.getElementById("list");
var li = document.createElement("li");
var children = ul.children.length + 1
li.setAttribute("id", "element"+children)
li.appendChild(document.createTextNode("Element "+children));
ul.appendChild(li)
}
Check this example that add li element to ul.

Just use innerHTML:
function function1() {
ul.innerHTML += `<li> four </li>`;
}

Text input inserting wrong value into list item

Here is my code: http://jsfiddle.net/H5bRH/
Every time I click on the submit button, it should insert what I typed into a new li item.
But instead of that, it inserts what I typed the first time PLUS the new value that I typed. Play with my jsfiddle to see what I mean.
How do I fix this so that it only adds what the user inputs into the form?
I assume there's something wrong here:
function saveTweet() {
var tweet = document.getElementById("tweet");
var tweetName = tweet.value;
var li = document.createElement("li");
li.innerHTML = tweetName;
var ul = document.getElementById("tweets");
ul.appendChild(li);
}

You have attached 2 click event to save button.
button.onclick = saveTweet;
Using jQuery $("#saveTweet").click(function ()
$("#saveTweet").click(function () {
var tweet = document.getElementById("tweet");
var tweetName = tweet.value;
var li = document.createElement("li");
li.innerHTML = tweetName;
var ul = document.getElementById("tweets");
ul.appendChild(li);
$("li").slideDown("fast");
});
JSFiddle

Why not just reduce all that code to :
$("#saveTweet").click(function () {
$('#tweets').append('<li>' + $("#tweet").val() + '</li>')
$("li").slideDown("fast");
});
jsFiddle example

Instead of having two click handlers for the #saveTweet button, move the slideDown call to your saveTweet function.
function saveTweet() {
var tweet = document.getElementById("tweet");
var tweetName = tweet.value;
var li = document.createElement("li");
li.innerHTML = tweetName;
var ul = document.getElementById("tweets");
ul.appendChild(li);
$("li").slideDown("fast");
}

It happens because you bind two click handlers on the #saveTweet element.
One to add the content, and one to animate the li elements..
In your case the animated one is occuring first and the appending second.. so you always animate the previously added element...
Since you use jQuery anyway, why not use that for all your interactions ?
$(function () {
var button = $("#saveTweet");
button.on('click', function () {
var tweet = $("#tweet"),
ul = $("#tweets"),
tweetName = tweet.val(),
li = $('<li>', {html: tweetName});
ul.append(li);
li.slideDown("fast");
});
});
Demo at http://jsfiddle.net/gaby/Y9cY3/1/