rotating with javascript

I just need some quick help, I am trying to use the JavaScript option such as this one:
<script type=”text/javascript” src=”http://www.mysite.com/wp-content/plugins/hms-testimonials/js.php?group=4&template=9″></script&gt;

but I whant it to show 1 testimonial at a time and rotate, how would I go about doing this, and is there a way to set the speed?

Thank you
Marco

https://ww.wp.xz.cn/plugins/hms-testimonials/