what does $(document).ready(function() mean code example

Example 1: jquery document ready

// jQuery document ready
$(document).ready(function() {
    
});

Example 2: document.ready

// A $( document ).ready() block.
$( document ).ready(function() {
    console.log( "ready!" );
});

Example 3: jquery document ready

The .ready() method is typically used with an anonymous function:
$( document ).ready(function() {
  // Handler for .ready() called.
});

Which is equivalent to the recommended way of calling:
$(function() {
  // Handler for .ready() called.
});