JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

div{
    box-sizing: border-box;
}

.container{
    width: 100%;
    height: 100%;
}

.element{
    width: 20%;
    height: 30px;
    float: left;
    background-color: red;
    border: 1px solid black;
}

JavaScript

var
  i,
  $container = $( '.container' ),
  $element1  = $container.find( '.element' ),
  $element2  = $( '.element', $container ),
  $element3  = $( '.element' ),
  element_html = ''
    + '<div class="element">'
      + '<span>I am an element</span>'
    + '</div>';

for( i=0; i<10; ++i ){
  $container.append( $(element_html) );  
}

console.log( "1: " + $element1.length + " instead of: " + $container.find( '.element' ).length );
console.log( "2: " + $element2.length + " instead of: " + $( '.element', $container )  .length );
console.log( "3: " + $element3.length + " instead of: " + $( '.element' )              .length );