Appending HTML string to the DOM

How to append a HTML string such as

var str = '<p>Just some <span>text</span> here</p>';

to the <div> with the id test?

(Btw div.innerHTML += str; is not acceptable.)

Use insertAdjacentHTML which is supported in all current browsers:

div.insertAdjacentHTML( 'beforeend', str );

The position parameter beforeend will add inside the element, after its last child.

Live demo: http://jsfiddle.net/euQ5n/

Performance

AppendChild (E) is more than 2x faster than other solutions on chrome and safari, insertAdjacentHTML(F) is fastest on firefox. The innerHTML= (B) (do not confuse with += (A)) is second fast solution on all browsers and it is much more handy than E and F.

Details

Set up environment (2019.07.10) MacOs High Sierra 10.13.4 on Chrome 75.0.3770 (64-bit), Safari 11.1.0 (13604.5.6), Firefox 67.0.0 (64-bit)

• on Chrome E (140k operations per second) is fastest, B (47k) and F (46k) are second, A (332) is slowest
• on firefox F (94k) is fastest, then B(80k), D (73k), E(64k), C (21k) slowest is A(466)
• on Safari E(207k) is fastest, then B(89k), F(88k), D(83k), C (25k), slowest is A(509)

You can replay test in your machine here

function A() {    
  container.innerHTML += '<p>A: Just some <span>text</span> here</p>';
}

function B() {    
  container.innerHTML = '<p>B: Just some <span>text</span> here</p>';
}

function C() {    
  $('#container').append('<p>C: Just some <span>text</span> here</p>');
}

function D() {
  var p = document.createElement("p");
  p.innerHTML = 'D: Just some <span>text</span> here';
  container.appendChild(p);
}

function E() {    
  var p = document.createElement("p");
  var s = document.createElement("span"); 
  s.appendChild( document.createTextNode("text ") );
  p.appendChild( document.createTextNode("E: Just some ") );
  p.appendChild( s );
  p.appendChild( document.createTextNode(" here") );
  container.appendChild(p);
}

function F() {    
  container.insertAdjacentHTML('beforeend', '<p>F: Just some <span>text</span> here</p>');
}

A();
B();
C();
D();
E();
F();

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

This snippet only for show code used in test (in jsperf.com) - it not perform test itself. 
<div id="container"></div>

Is this acceptable?

var child = document.createElement('div');
child.innerHTML = str;
child = child.firstChild;
document.getElementById('test').appendChild(child);

jsFiddle.

But, Neil's answer is a better solution.

The idea is to use innerHTML on an intermediary element and then move all of its child nodes to where you really want them via appendChild.

var target = document.getElementById('test');
var str = '<p>Just some <span>text</span> here</p>';

var temp = document.createElement('div');
temp.innerHTML = str;
while (temp.firstChild) {
  target.appendChild(temp.firstChild);
}

This avoids wiping out any event handlers on div#test but still allows you to append a string of HTML.

The right way is using insertAdjacentHTML. In Firefox earlier than 8, you can fall back to using Range.createContextualFragment if your str contains no script tags.

If your str contains script tags, you need to remove script elements from the fragment returned by createContextualFragment before inserting the fragment. Otherwise, the scripts will run. (insertAdjacentHTML marks scripts unexecutable.)

Quick Hack:

---

<script>
document.children[0].innerHTML="<h1>QUICK_HACK</h1>";
</script>

---

Use Cases:

1: Save as .html file and run in chrome or firefox or edge. (IE wont work)

2: Use in http://js.do

In Action: http://js.do/HeavyMetalCookies/quick_hack

Broken down with comments:

<script>
  
//: The message "QUICK_HACK" 
//: wrapped in a header #1 tag.
var text = "<h1>QUICK_HACK</h1>";

//: It's a quick hack, so I don't
//: care where it goes on the document,
//: just as long as I can see it.
//: Since I am doing this quick hack in
//: an empty file or scratchpad, 
//: it should be visible.
var child = document.children[0];

//: Set the html content of your child
//: to the message you want to see on screen.
child.innerHTML = text;

</script>

Reason Why I posted:

JS.do has two must haves:

1. No autocomplete
2. Vertical monitor friendly

But doesn't show console.log messages. Came here looking for a quick solution. I just want to see the results of a few lines of scratchpad code, the other solutions are too much work.

Why is that not acceptable?

document.getElementById('test').innerHTML += str

would be the textbook way of doing it.

This can solve

 document.getElementById("list-input-email").insertAdjacentHTML('beforeend', '<div class=""><input type="text" name="" value="" class="" /></div>');

InnerHTML clear all data like event for existing nodes

append child with firstChild adds only first child to innerHTML. For example if we have to append:

 <p>text1</p><p>text2</p>

only text1 will show up

What about this:

adds special tag to innerHTML by append child and then edit outerHTML by deleting tag we've created. Don't know how smart it is but it works for me or you might change outerHTML to innerHTML so it doesn't have to use function replace

function append(element, str)
{

  var child = document.createElement('someshittyuniquetag');
		
  child.innerHTML = str;

  element.appendChild(child);

  child.outerHTML = child.outerHTML.replace(/<\/?someshittyuniquetag>/, '');

// or Even child.outerHTML = child.innerHTML

}

<div id="testit">
This text is inside the div
<button onclick="append(document.getElementById('testit'), '<button>dadasasdas</button>')">To div</button>
<button onclick="append(this, 'some text')">to this</button>
</div>

Shortest - 18 chars (not confuse += (mention by OP) with = more details here)

test.innerHTML=str

var str = '<p>Just some <span>text</span> here</p>';

test.innerHTML=str

<div id="test"></div>