when page is loader one function call in jquery code example

Example 1: call a function on load jquery

$(document).ready(function () {
  // Function code here.
});

Example 2: jquery check if document loaded

jQuery offers several ways to attach a function that will run when the DOM is ready. All of the following syntaxes are equivalent:

$( handler )
$( document ).ready( handler )
$( "document" ).ready( handler )
$( "img" ).ready( handler )
$().ready( handler )