Develop Reference

How do we convert jQuery prepend() to VanillaJS [duplicate]

How can I implement prepend and append with regular JavaScript without using jQuery?

Here's a snippet to get you going:
theParent = document.getElementById("theParent");
theKid = document.createElement("div");
theKid.innerHTML = 'Are we there yet?';
// append theKid to the end of theParent
theParent.appendChild(theKid);
// prepend theKid to the beginning of theParent
theParent.insertBefore(theKid, theParent.firstChild);
theParent.firstChild will give us a reference to the first element within theParent and put theKid before it.

Perhaps you're asking about the DOM methods appendChild and insertBefore.
parentNode.insertBefore(newChild, refChild)
Inserts the node newChild as a child of parentNode before the
existing child node refChild. (Returns newChild.)
If refChild is null, newChild is added at the end of the list of
children. Equivalently, and more readably, use
parentNode.appendChild(newChild).

You didn't give us much to go on here, but I think you're just asking how to add content to the beginning or end of an element?
If so here's how you can do it pretty easily:
//get the target div you want to append/prepend to
var someDiv = document.getElementById("targetDiv");
//append text
someDiv.innerHTML += "Add this text to the end";
//prepend text
someDiv.innerHTML = "Add this text to the beginning" + someDiv.innerHTML;
Pretty easy.

If you want to insert a raw HTML string no matter how complex, you can use:
insertAdjacentHTML, with appropriate first argument:
'beforebegin'
Before the element itself.
'afterbegin'
Just inside the element, before its first child.
'beforeend'
Just inside the element, after its last child.
'afterend'
After the element itself.
Hint: you can always call Element.outerHTML to get the HTML string representing the element to be inserted.
An example of usage:
document.getElementById("foo").insertAdjacentHTML("beforeBegin",
"<div><h1>I</h1><h2>was</h2><h3>inserted</h3></div>");
DEMO
Caution: insertAdjacentHTML does not preserve listeners that where attached with .addEventLisntener.

I added this on my project and it seems to work:
HTMLElement.prototype.prependHtml = function (element) {
const div = document.createElement('div');
div.innerHTML = element;
this.insertBefore(div, this.firstChild);
};
HTMLElement.prototype.appendHtml = function (element) {
const div = document.createElement('div');
div.innerHTML = element;
while (div.children.length > 0) {
this.appendChild(div.children[0]);
}
};
Example:
document.body.prependHtml(`Hello World`);
document.body.appendHtml(`Hello World`);

Here's an example of using prepend to add a paragraph to the document.
var element = document.createElement("p");
var text = document.createTextNode("Example text");
element.appendChild(text);
document.body.prepend(element);
result:
<p>Example text</p>

In order to simplify your life you can extend the HTMLElement object. It might not work for older browsers, but definitely makes your life easier:
HTMLElement = typeof(HTMLElement) != 'undefined' ? HTMLElement : Element;
HTMLElement.prototype.prepend = function(element) {
if (this.firstChild) {
return this.insertBefore(element, this.firstChild);
} else {
return this.appendChild(element);
}
};
So next time you can do this:
document.getElementById('container').prepend(document.getElementById('block'));
// or
var element = document.getElementById('anotherElement');
document.body.prepend(div);

In 2017 I know for Edge 15 and IE 12, the prepend method isn't included as a property for Div elements, but if anyone needs a quick reference to polyfill a function I made this:
HTMLDivElement.prototype.prepend = (node, ele)=>{
try { node.insertBefore(ele ,node.children[0]);}
catch (e){ throw new Error(e.toString()) } }
Simple arrow function that's compatible with most modern browsers.

var insertedElement = parentElement.insertBefore(newElement, referenceElement);
If referenceElement is null, or undefined, newElement is inserted at the end of the list of child nodes.
insertedElement The node being inserted, that is newElement
parentElement The parent of the newly inserted node.
newElement The node to insert.
referenceElement The node before which newElement is inserted.
Examples can be found here: Node.insertBefore

You can also use unshift() to prepend to a list

document.write() is not a good practice, some browsers like Chrome give you a warning if you use it, and it may be a bad solution if you are providing it to a customer, they don't want to use your code and see warnings in the debug console!
Also jQuery may also be a bad thing if you are giving your code to a customer who already uses jQuery for other functionality on their site, there will be a conflict if there is already a different version of jQuery running.
If you want to insert content into an iframe, and do that with pure JS, and with no JQuery, and without document.write(), I have a solution.
You can use the following steps
1.Select your iframe:
var iframe = document.getElementById("adblock_iframe");
2.Create an element that you want to insert into the frame, let's say an image:
var img = document.createElement('img');
img.src = "https://server-name.com/upload/adblock" + id + ".jpg";
img.style.paddingLeft = "450px";
//scale down the image is we have a high resolution screen on the client side
if (retina_test_media == true && high_res_test == true) {
img.style.width = "200px";
img.style.height = "50px";
} else {
img.style.width = "400px";
img.style.height = "100px";
}
img.id = "image";
3.Insert the image element into the iframe:
iframe.contentWindow.document.body.appendChild(img);

This is not best way to do it but if anyone wants to insert an element before everything, here is a way.
var newElement = document.createElement("div");
var element = document.getElementById("targetelement");
element.innerHTML = '<div style="display:none !important;"></div>' + element.innerHTML;
var referanceElement = element.children[0];
element.insertBefore(newElement,referanceElement);
element.removeChild(referanceElement);

navigating the dom javascript specific tag

Here it is DOM structure:
<div id="some">
NOTHIS
NOTHIS
<h3 class="myclass">HELLO</h3>
</div>
How can I get the value of HELLO in javascript?
EDIT: Forgot, I have other anchor tags inside 'some', so I want strictly the anchor tag inside the h3's
EDIT2: Got it:
var n = document.getElementById('some').getElementsByTagName('h3')[0].getElementsByTagName('a')[0].innerHTML;
Thanks all!

var linkText = document.getElementById('some').getElementsByTagName('a')[0].innerHTML;
or if you have jQuery
var linkText = $('#some').find('a').html();

var anchor = document.getElementById('some').getElementsByTagName('a')[0],
yourText = anchor.innerText || anchor.textContent;
It's cross-browser, too. http://www.quirksmode.org/dom/w3c_html.html

Propagate down the DOM from your ID.
var s = document.getElementById('some').getElementsByTagName('h3')[0].getElementsByTagName('a')[0].innerHTML;
I would put an ID on the a myself.

var shouldEqualHello = document.getElementById('some').getElementsByTagName('h3')[0].getElementsByTagName('a')[0].innerHTML;
edit: fixed

to get to a single dom element with javascript, you need a way to uniquely identify it. the ideal approach is to give your element a unique id.
<a id="myAnchor" href="#" style="color:red;">HELLO</a>
then you can directly obtain a reference in script.
var myAnchor = document.getElementById('myAnchor');
or if you are guaranteed that your element is the only anchor element within the "some" id you can do
var someDiv = document.getElementById('some');
var anchors = someDiv.getElementsByTagName('a'); // returns a list of anchor elements
var myAnchor = anchors[0]; // get the first element in the list
but since that's not the case you'll have to pick your way down through the dom some more.
var someDiv = document.getElementById('some');
var headers = someDiv.getElementsByTagName('h3');
var myH3 = headers[0];
var anchors = myH3 .getElementsByTagName('a'); // returns a list of anchor elements
var myAnchor = anchors[0]; // get the first element in the list
from there you can see the stuff between the tags with
alert(myAnchor.innerHTML);
or
alert(myAnchor.firstChild.nodeValue);
or some other method already mentioned here.

You could simply use query selector,
let result = document.querySelector('#some h3 a').innerText;
console.log(result);

How can I implement prepend and append with regular JavaScript?

How can I implement prepend and append with regular JavaScript without using jQuery?

Here's a snippet to get you going:
theParent = document.getElementById("theParent");
theKid = document.createElement("div");
theKid.innerHTML = 'Are we there yet?';
// append theKid to the end of theParent
theParent.appendChild(theKid);
// prepend theKid to the beginning of theParent
theParent.insertBefore(theKid, theParent.firstChild);
theParent.firstChild will give us a reference to the first element within theParent and put theKid before it.

Perhaps you're asking about the DOM methods appendChild and insertBefore.
parentNode.insertBefore(newChild, refChild)
Inserts the node newChild as a child of parentNode before the
existing child node refChild. (Returns newChild.)
If refChild is null, newChild is added at the end of the list of
children. Equivalently, and more readably, use
parentNode.appendChild(newChild).

You didn't give us much to go on here, but I think you're just asking how to add content to the beginning or end of an element?
If so here's how you can do it pretty easily:
//get the target div you want to append/prepend to
var someDiv = document.getElementById("targetDiv");
//append text
someDiv.innerHTML += "Add this text to the end";
//prepend text
someDiv.innerHTML = "Add this text to the beginning" + someDiv.innerHTML;
Pretty easy.

If you want to insert a raw HTML string no matter how complex, you can use:
insertAdjacentHTML, with appropriate first argument:
'beforebegin'
Before the element itself.
'afterbegin'
Just inside the element, before its first child.
'beforeend'
Just inside the element, after its last child.
'afterend'
After the element itself.
Hint: you can always call Element.outerHTML to get the HTML string representing the element to be inserted.
An example of usage:
document.getElementById("foo").insertAdjacentHTML("beforeBegin",
"<div><h1>I</h1><h2>was</h2><h3>inserted</h3></div>");
DEMO
Caution: insertAdjacentHTML does not preserve listeners that where attached with .addEventLisntener.

I added this on my project and it seems to work:
HTMLElement.prototype.prependHtml = function (element) {
const div = document.createElement('div');
div.innerHTML = element;
this.insertBefore(div, this.firstChild);
};
HTMLElement.prototype.appendHtml = function (element) {
const div = document.createElement('div');
div.innerHTML = element;
while (div.children.length > 0) {
this.appendChild(div.children[0]);
}
};
Example:
document.body.prependHtml(`Hello World`);
document.body.appendHtml(`Hello World`);

Here's an example of using prepend to add a paragraph to the document.
var element = document.createElement("p");
var text = document.createTextNode("Example text");
element.appendChild(text);
document.body.prepend(element);
result:
<p>Example text</p>

In order to simplify your life you can extend the HTMLElement object. It might not work for older browsers, but definitely makes your life easier:
HTMLElement = typeof(HTMLElement) != 'undefined' ? HTMLElement : Element;
HTMLElement.prototype.prepend = function(element) {
if (this.firstChild) {
return this.insertBefore(element, this.firstChild);
} else {
return this.appendChild(element);
}
};
So next time you can do this:
document.getElementById('container').prepend(document.getElementById('block'));
// or
var element = document.getElementById('anotherElement');
document.body.prepend(div);

In 2017 I know for Edge 15 and IE 12, the prepend method isn't included as a property for Div elements, but if anyone needs a quick reference to polyfill a function I made this:
HTMLDivElement.prototype.prepend = (node, ele)=>{
try { node.insertBefore(ele ,node.children[0]);}
catch (e){ throw new Error(e.toString()) } }
Simple arrow function that's compatible with most modern browsers.

var insertedElement = parentElement.insertBefore(newElement, referenceElement);
If referenceElement is null, or undefined, newElement is inserted at the end of the list of child nodes.
insertedElement The node being inserted, that is newElement
parentElement The parent of the newly inserted node.
newElement The node to insert.
referenceElement The node before which newElement is inserted.
Examples can be found here: Node.insertBefore

You can also use unshift() to prepend to a list

document.write() is not a good practice, some browsers like Chrome give you a warning if you use it, and it may be a bad solution if you are providing it to a customer, they don't want to use your code and see warnings in the debug console!
Also jQuery may also be a bad thing if you are giving your code to a customer who already uses jQuery for other functionality on their site, there will be a conflict if there is already a different version of jQuery running.
If you want to insert content into an iframe, and do that with pure JS, and with no JQuery, and without document.write(), I have a solution.
You can use the following steps
1.Select your iframe:
var iframe = document.getElementById("adblock_iframe");
2.Create an element that you want to insert into the frame, let's say an image:
var img = document.createElement('img');
img.src = "https://server-name.com/upload/adblock" + id + ".jpg";
img.style.paddingLeft = "450px";
//scale down the image is we have a high resolution screen on the client side
if (retina_test_media == true && high_res_test == true) {
img.style.width = "200px";
img.style.height = "50px";
} else {
img.style.width = "400px";
img.style.height = "100px";
}
img.id = "image";
3.Insert the image element into the iframe:
iframe.contentWindow.document.body.appendChild(img);

This is not best way to do it but if anyone wants to insert an element before everything, here is a way.
var newElement = document.createElement("div");
var element = document.getElementById("targetelement");
element.innerHTML = '<div style="display:none !important;"></div>' + element.innerHTML;
var referanceElement = element.children[0];
element.insertBefore(newElement,referanceElement);
element.removeChild(referanceElement);

Javascript DOM howto?

I am a javascript noob.
I would like to select the second 'p' element of the div.box.
How do I do this?
Thanks a lot!
Tom

To get second p element of div with class box you'd do this:
var paragraph = null;
var divs = document.findElementsByTagName('div');
for (var i = 0; i < divs.length; i++) {
var div = divs[i];
if (div.class == 'box') {
var paragraphs = div.getElementsByTagName('p');
if (paragraphs.length > 1)
paragraph = paragraphs[1];
break;
}
}
The paragraph would then be in the paragraph variable (or null if it wasn't found).
However you can do this much easier with a library such as jQuery:
var paragraph = $('div.box p:eq(1)');

Without using jQuery, the basic method would be to attach an unique ID to your Dom element
<p id="second_p_elmt"> [...] </p>
and then accessing it through the getElementById() method:
<script ...>
var second_p_elmt = document.getElementById('second_p_elmt');
</script>

<script type="text/javascript">
var boxElem = document.getElementById('box'),
pElems = boxElem.getElementsByTagName('p'),
whatYouWant = pElems[1]; // [1] is the second element in the response from getElementsByTagName
</script>

You have several options. As stated above, you could use one of the excellent frameworks, like jQuery or prototype. Or you give the <p/> an ID, that you can use simply with document.getElementById().
Then, as reko_t pointed out, without the above, you must write a lengthy DOM traversing code (which is preferable, if you don't use JS frameworks elsewhere, over embedding them only for this task).
In the most recent browsers (namely, IE>=8, FF>=3.5, recent Opera and Safari > 3) you can also use this simple snippet:
var p = document.querySelectorAll("div.box p");

How to replace DOM element in place using Javascript?

I am looking to replace an element in the DOM.
For example, there is an <a> element that I want to replace with a <span> instead.
How would I go and do that?

by using replaceChild():
<html>
<head>
</head>
<body>
<div>
<a id="myAnchor" href="http://www.stackoverflow.com">StackOverflow</a>
</div>
<script type="text/JavaScript">
var myAnchor = document.getElementById("myAnchor");
var mySpan = document.createElement("span");
mySpan.innerHTML = "replaced anchor!";
myAnchor.parentNode.replaceChild(mySpan, myAnchor);
</script>
</body>
</html>

A.replaceWith(span) - No parent needed
Generic form:
target.replaceWith(element)
Way better/cleaner than the previous method.
For your use case:
A.replaceWith(span)
Advanced usage
You can pass multiple values (or use spread operator ...).
Any string value will be added as a text element.
Examples:
// Initially [child1, target, child3]
target.replaceWith(span, "foo") // [child1, span, "foo", child3]
const list = ["bar", span]
target.replaceWith(...list, "fizz") // [child1, "bar", span, "fizz", child3]
Safely handling null target
If your target has a chance to be null, you can consider using the newish ?. optional chaining operator. Nothing will happen if target doesn't exist. Read more here.
target?.replaceWith?.(element)
Related DOM methods
Read More - child.before and child.after
Read More - parent.prepend and parent.append
Mozilla Docs
Supported Browsers - 97% Nov '22

var a = A.parentNode.replaceChild(document.createElement("span"), A);
a is the replaced A element.

This question is very old, but I found myself studying for a Microsoft Certification, and in the study book it was suggested to use:
oldElement.replaceNode(newElement)
I looked it up and it seems to only be supported in IE. Doh..
I thought I'd just add it here as a funny side note ;)

I had a similar issue and found this thread. Replace didn't work for me, and going by the parent was difficult for my situation. Inner Html replaced the children, which wasn't what I wanted either. Using outerHTML got the job done. Hope this helps someone else!
currEl = <div>hello</div>
newElem = <span>Goodbye</span>
currEl.outerHTML = newElem
# currEl = <span>Goodbye</span>

You can replace an HTML Element or Node using Node.replaceWith(newNode).
This example should keep all attributes and childs from origin node:
const links = document.querySelectorAll('a')
links.forEach(link => {
const replacement = document.createElement('span')
// copy attributes
for (let i = 0; i < link.attributes.length; i++) {
const attr = link.attributes[i]
replacement.setAttribute(attr.name, attr.value)
}
// copy content
replacement.innerHTML = link.innerHTML
// or you can use appendChild instead
// link.childNodes.forEach(node => replacement.appendChild(node))
link.replaceWith(replacement)
})
If you have these elements:
Link 1
Link 2
Link 3
Link 4
After running above codes, you will end up with these elements:
<span href="#link-1">Link 1</span>
<span href="#link-2">Link 2</span>
<span href="#link-3">Link 3</span>
<span href="#link-4">Link 4</span>

You can use replaceChild on the parent of the target element after creating your new element (createElement):
const newElement = document.createElement(/*...*/);
const target = document.getElementById("my-table");
target.parentNode.replaceChild(newElement, target);
If your starting point for the new element is HTML, you can use insertAdjacentHTML and then removeChild on the parent (or remove on the element itself, in modern environments):
const target = document.getElementById("my-table");
target.insertAdjacentHTML("afterend", theHTMLForTheNewElement);
target.parentNode.removeChild(target); // Or: `target.remove()`

Best way to do it. No parents need. Just use Element.outerHTML = template;
// Get the current element
var currentNode = document.querySelector('#greeting');
// Replace the element
currentNode.outerHTML =
'<div id="salutations">' +
'<h1>Hi, universe!</h1>' +
'<p>The sun is always shining!</p>' +
'</div>';

Example for replacing LI elements
function (element) {
let li = element.parentElement;
let ul = li.parentNode;
if (li.nextSibling.nodeName === 'LI') {
let li_replaced = ul.replaceChild(li, li.nextSibling);
ul.insertBefore(li_replaced, li);
}
}

Given the already proposed options the easiest solution without finding a parent:
var parent = document.createElement("div");
var child = parent.appendChild(document.createElement("a"));
var span = document.createElement("span");
// for IE
if("replaceNode" in child)
child.replaceNode(span);
// for other browsers
if("replaceWith" in child)
child.replaceWith(span);
console.log(parent.outerHTML);