Sample widget template

gistfile1.php

<?php
/**
 * Sample widget
 *
 * @since 1.0.0.0
 */
class ja_sample_Widget extends WP_Widget {

	/**
	 * Holds widget settings defaults, populated in constructor.
	 *
	 * @since 1.0.0
	 * @var array
	 */
	protected $defaults;

	/**
	 * Constructor
	 *
	 * @since 1.0.0
	 */
	function __construct() {

		// widget defaults
		$this->defaults = array(
			'title' => '',
			'text' => '',
		);

		// widget basics
		$widget_ops = array(
			'classname'   => 'ja-sample-widget',
			'description' => 'Widget description goes here.'
		);

		// widget controls
		$control_ops = array(
			'id_base' => 'ja-sample-widget',
			'width'   => 400,
		);

		// load widget
		$this->WP_Widget( 'ja-sample-widget', 'JA Sample Widget', $widget_ops, $control_ops );

	}

	/**
     * Outputs the HTML for this widget.
     *
     * @since 1.0.0
     * @param array $args An array of standard parameters for widgets in this theme 
     * @param array $instance An array of settings for this widget instance 
     */
	function widget( $args, $instance ) {

		extract( $args );

		// Merge with defaults
		$instance = wp_parse_args( (array) $instance, $this->defaults );

		echo $before_widget;

			// Title
			if ( !empty( $instance['title'] ) ) { 
				echo $before_title . $instance['title'] . $after_title;
			}

			// Text
			if ( !empty( $instance['text'] ) ) {
				echo esc_html( $instance['text'] );
			}

		echo $after_widget;
	}

	/**
     * Deals with the settings when they are saved by the admin. Here is
     * where any validation should be dealt with.
     *
     * @since 1.0.0
     * @param array $new_instance An array of new settings as submitted by the admin
     * @param array $old_instance An array of the previous settings 
     * @return array The validated and (if necessary) amended settings
     */
	function update( $new_instance, $old_instance ) {

		$new_instance['title'] = strip_tags( $new_instance['title'] );
		$new_instance['text'] = esc_html( $new_instance['text'] );

		return $new_instance;
	}

	/**
     * Displays the form for this widget on the Widgets page of the WP Admin area.
     *
     * @since 1.0.0
     * @param array $instance An array of the current settings for this widget
     */
	function form( $instance ) {

		// Merge with defaults
		$instance = wp_parse_args( (array) $instance, $this->defaults );
		?>
		<p>
			<label for="<?php echo $this->get_field_id( 'title' ); ?>">Title:</label>
			<input type="text" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" value="<?php echo esc_attr( $instance['title'] ); ?>" class="widefat" />
		</p>
		<p>
			<label for="<?php echo $this->get_field_id( 'text' ); ?>">Text:</label>
			<input type="text" id="<?php echo $this->get_field_id( 'text' ); ?>" name="<?php echo $this->get_field_name( 'text' ); ?>" value="<?php echo esc_attr( $instance['text'] ); ?>" class="widefat" />
		</p>
		<?php
	}
}
add_action( 'widgets_init', create_function( '', "register_widget('ja_sample_Widget');" ) );