How to Include jQuery in wordpress using code.

Standard method to include jQuery in your wordpress site

add_action('init', 'myplugin_load');

function myplugin_load(){
    wp_enqueue_script( 'jquery' );
    wp_enqueue_script( 'jquery-ui-core' );
    wp_enqueue_script( 'jquery-ui-dialog' );
}

For styling

wp_enqueue_style("wp-jquery-ui-dialog");

For Add dialog JS:

var dlg = $("<div id='myFancyDialog' />")

  .text('content')

  .appendTo("body");


dlg.dialog({

    'dialogClass'   : 'wp-dialog',

    'modal'         : true,

    'autoOpen'      : false,

    'closeOnEscape' : true,

    'buttons'       : [

        {

            'text' : 'Close',

            'class' : 'button-primary',

            'click' : function() {

                $(this).dialog('close');

            }

        }

    ]

}).dialog('open');