how to create a widget using code wordpress

 <?php

// Creating the widget 

class wpb_widget extends WP_Widget {

  

function __construct() {

parent::__construct(

  

// Base ID of your widget

'wpb_widget', 

  

// Widget name will appear in UI

__('WPBeginner Widget', 'wpb_widget_domain'), 

  

// Widget description

array( 'description' => __( 'Sample widget based on WPBeginner Tutorial', 'wpb_widget_domain' ), ) 

);

}

  

// Creating widget front-end

  

public function widget( $args, $instance ) {

$title = apply_filters( 'widget_title', $instance['title'] );

  

// before and after widget arguments are defined by themes

echo $args['before_widget'];

if ( ! empty( $title ) )

echo $args['before_title'] . $title . $args['after_title'];

echo $title;

?>

<input type="text" class="widefat"><input type="button" id="btn">

<script>

(function($)

{

$("#btn").bind('click',function(e)

{

alert();

});

}(jQuery));

</script>

<?php 

// This is where you run the code and display the output

echo __( 'Hello, World!', 'wpb_widget_domain' );

echo $args['after_widget'];

}

          

// Widget Backend 

public function form( $instance ) {

if ( isset( $instance[ 'title' ] ) ) {

$title = $instance[ 'title' ];

}

else {

$title = __( 'New title', 'wpb_widget_domain' );

}

// Widget admin form

?>

<p>

<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label> 

<input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>" />

<textarea name="<?php echo $this->get_field_name( 'textarea' ); ?>" class="widefat">

<?php echo esc_attr( $instance['textarea']); ?>

</textarea>

</p>

<?php 

}

      

// Updating widget replacing old instances with new

public function update( $new_instance, $old_instance ) {

$instance = array();

$instance['textarea'] = $new_instance['textarea'];

$instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';

return $instance;

}

 

// Class wpb_widget ends here

} 

 

 

// Register and load the widget

function wpb_load_widget() {

    register_widget( 'wpb_widget' );

}

add_action( 'widgets_init', 'wpb_load_widget' );