Check JavaScript Message Queue Behavior: Particularly UI Event filtering timing

test.html

<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>

<button id="a" onclick="A();">asdf</button>
<button id="b" onclick="B();">zxcv</button>

<script>

function C () {
  for ( var i = 0; i < 65535; i += 2 ) {
    i = i - 1;
  }
}

function A () {
  console.log( "A starts" );
  setTimeout( function () {
    $("#b").prop( "disabled", true );
  }, 1000 );
  for ( var i = 0; i < 65535; i++ ) {
    C();
  }
  console.log( "A ends" );
}

function B () {
  console.log( "B starts" );
  // $("#a").prop( "disabled", true );
  // $("#a").click();
  console.log( "B ends" );
}

</script>