Run results for: Element by ID fetching. Javascript vs selectors.

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0

Browser: Firefox 60

Operating system: Windows

Device Platform: Other

Date tested: 6 years ago

Test name	Executions per second
1 div with javascript	1818191.0 Ops/sec
1 div with jquery selector	2064467.0 Ops/sec
2 divs with javascript. Add with jquery	507530.6 Ops/sec
2 divs with 2 jquery selectors. Add with jquery	544267.6 Ops/sec
2 divs with javascript. Add with array	871396.4 Ops/sec
2 divs with 2 jquery selectors. Add with array	770025.4 Ops/sec
2 divs with single jquery selector	397.1 Ops/sec
1 div with jquery selector with context	487338.9 Ops/sec

HTML Preparation code:

<script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.1.0.min.js"></script>

Script Preparation code:

//Add 100,000 elements
var frag = document.createDocumentFragment();
for (var i=0; i<10; i++){
  var outDiv = document.createElement('div');
  for (var j=0; j<100; j++){
    var midDiv = document.createElement('div');
    for (var k=0; k<100; k++){
      var inDiv = document.createElement('div');
      if(i==6 && j==60){
        if(k==60)
          inDiv.id="one";
        else if(k==61)
          inDiv.id="two";
      }
      midDiv.appendChild(inDiv)
    }
    outDiv.appendChild(midDiv)
  }
  frag.appendChild(outDiv);
}
document.body.appendChild(frag);

Tests:

1 div with javascript
var $obj = $(document.getElementById('one')); if($obj.length!=1) throw Error("Fail")
1 div with jquery selector
var $obj = $('#one'); if($obj.length!=1) throw Error("Fail")
2 divs with javascript. Add with jquery
var $obj = $(document.getElementById('one')).add(document.getElementById('two')); if($obj.length!=2) throw Error("Fail")
2 divs with 2 jquery selectors. Add with jquery
var $obj = $('#one').add('#two'); if($obj.length!=2) throw Error("Fail")
2 divs with javascript. Add with array
var $obj = $([document.getElementById('one'),document.getElementById('two')]); if($obj.length!=2) throw Error("Fail")
2 divs with 2 jquery selectors. Add with array
var $obj = $([$('#one')[0],$('#two')[0]]); if($obj.length!=2) throw Error("Fail")
2 divs with single jquery selector
var $obj = $('#one, #two'); if($obj.length!=2) throw Error("Fail")
1 div with jquery selector with context
var $obj = $(document.body).find('#one'); if($obj.length!=1) throw Error("Fail")

Run results for: Element by ID fetching. Javascript vs selectors.

Fetching elements into a jquery object using different means. Multiple calls to document.getElementByID vs comma separated selector.

1 div with javascript

1 div with jquery selector

2 divs with javascript. Add with jquery

2 divs with 2 jquery selectors. Add with jquery

2 divs with javascript. Add with array

2 divs with 2 jquery selectors. Add with array

2 divs with single jquery selector

1 div with jquery selector with context