Plugin has an error.

Hi I am using jwplatform.
When I use this plugin, this plugin returns error.

If you go to your github site: https://github.com/mariusveltan/bits-on-the-run/blob/master/bitsontherun.php
line #89 make an error, because when the value is not exist. it makes syntex error like “botr.nr_videos = ; “

<script type=’text/javascript’>
botr.plugin_url = ‘<?php echo $plugin_url;?>’;
botr.api_proxy = ‘<?php echo $api_proxy;?>’;
botr.content_mask = ‘<?php echo $content_mask;?>’;
botr.nr_videos = <?php echo $nr_videos;?>;
</script>

Could you tell me why you don’t use ” like other lines?

botr.nr_videos = <?php echo $nr_videos;?>;

https://wordpress.org/plugins/bits-on-the-run/