use of triger in jquery code example

Example 1: jquery trigger

$( "#foo" ).on( "click", function() {
  alert( $( this ).text() );
});
$( "#foo" ).trigger( "click" );

$( "#foo" ).on( "custom", function( event, param1, param2 ) {
  alert( param1 + "\n" + param2 );
});
$( "#foo").trigger( "custom", [ "Custom", "Event" ] );

Example 2: trigger send parameter

$('body').trigger('this_works', [{data: [1, 2, 3]}, 'something']);

$('body').on('this_works', function (event, json, string) {
  // parameter is stocked in json.data here.
  console.log(event, json, string);
});