add element into another element #append #prepend

.append() Insert content, specified by the parameter, to the end of each element in the set of matched elements. .appendTo() is same task

<h2>Greetings</h2>
<div class="container">
  <div class="inner">Hello</div>
  <div class="inner">Goodbye</div>
</div>

$( ".inner" ).append( "<p>Test</p>" );
// $( "<p>Test</p>" ).appendTo( ".inner" ); // same

<h2>Greetings</h2>
<div class="container">
  <div class="inner"> <!-- target -->
    Hello
    <p>Test</p> <!-- new element -->
  </div>
  <div class="inner"> <!-- target -->
    Goodbye
    <p>Test</p> <!-- new element -->
  </div>
</div>

.prepend() Insert content, specified by the parameter, to the beginning of each element in the set of matched elements. .prependTo() is same task

	$( ".inner" ).prepend( "<p>Test</p>" ); 
	// $( "<p>Test</p>" ).prependTo( ".inner" ); // same

<h2>Greetings</h2>
<div class="container">
  <div class="inner"> <!-- target -->
    Hello
    <p>Test</p> <!-- new element -->
  </div>
  <div class="inner"> <!-- target -->
    Goodbye
    <p>Test</p> <!-- new element -->
  </div>
</div>

Ref:

khoand0000/add-element.md