class Slider_Control extends WP_Customize_Control{
    public $type = 'slider';

    public function render_content(){
        ?>
        <label>
            <span class="customize-control-title"><?php esc_html($this->label); ?>  </span>
            <p>Value: <?php echo $this->value; ?></p>
            <input type="hidden" value="<?php echo $this->value; ?>" />
        </label>
        <div class="slider"></div>
        <script type="text/javascript">
            jQuery(function(){
                jQuery('.slider').slider();
            });
        </script>
        <?php
    }
}