wp custom widget

// get sidebar
	<div class="cw_single">
		<?php get_sidebar(); ?>
	</div>

//Custom widget
<?php

class Adaptive_Ad_260_Widget extends WP_Widget {
	// widget init
	public function __construct() {
		parent::__construct(
			'adaptice_ad_w',
			'Custom Widget: 260x120 Ad',
			array('description' => __('Display a single 260x120 ad block', 'custom_widget')) //custom_widget text domain
		);
	}
	// output the widget options in the back-end
	public function form($instance) {
		$defaults = array(
			'title' => __('Ad 260x120', 'custom_widget'),
			'ad_img' => IMAGES . '/quote-format-icon.png',
			'ad_link' => 'http://wp.tutsplus.com',
			'dsc' => __('Description', 'custom_widget'),
		);

		$instance = wp_parse_args((array) $instance, $defaults);

		?>
			<!-- title -->
			<p>
				<label for="<?php echo $this->get_field_id('title') ?>"><?php _e('Title', 'custom_widget'); ?></label>
				<input type="text" id="<?php echo $this->get_field_id('title') ?>" name="<?php echo $this->get_field_name('title') ?>" class="widefat" value="<?php echo esc_attr($instance['title']); ?>">
			</p>

			<!-- ad image -->
			<p>
				<label for="<?php echo $this->get_field_id('ad_img') ?>"><?php _e('Ad Image', 'custom_widget'); ?></label>
				<input type="text" id="<?php echo $this->get_field_id('ad_img') ?>" name="<?php echo $this->get_field_name('ad_img') ?>" class="widefat" value="<?php echo esc_attr($instance['ad_img']); ?>">
			</p>
			<!-- ad link -->

			<p>
				<label for="<?php echo $this->get_field_id('ad_link') ?>"><?php _e('Ad Link', 'custom_widget'); ?></label>
				<input type="text" id="<?php echo $this->get_field_id('ad_link') ?>" name="<?php echo $this->get_field_name('ad_link') ?>" class="widefat" value="<?php echo esc_attr($instance['ad_link']); ?>">
			</p>



		<?php
	}

	// Process widget options for saving
	public function update($new_instance, $old_instance) {
		$instance = $old_instance;

		// Title
		$instance['title'] = strip_tags($new_instance['title']);

		// Ad image
		$instance['ad_img'] = strip_tags($new_instance['ad_img']);

		// Ad link
		$instance['ad_link'] = strip_tags($new_instance['ad_link']);

		return $instance;
	}

	// Display the widget on the page
	public function widget($args, $instance) {
		extract($args);

		$title = apply_filters('widget-title', $instance['title']);
		$ad_img = $instance['ad_img'];
		$ad_link = $instance['ad_link'];

		if ($title) {
			echo $before_title . $title . $after_title;
		}

		echo '<div class="cw_single">';
		if($ad_img) : ?>
			<a href="<?php echo $ad_link; ?>"><img src="<?php echo $ad_img ?>" alt=""></a>

			<?php endif;
		echo '</div>';
		echo $after_widget;
	}
}
register_widget('Adaptive_Ad_260_Widget');

 ?>