How to add a script code for WP Menu

Hi,

I want to add a custom item to my main menu for booking. It should work with Javascript. I tried a few suggestions but it doesn’t work. I want the visitors to run this script as they click “Book Now” on the menu.

Here is the code they gave to me:

<style type=’text/css’>@import url(http://app.hotelrunner.com/assets/widgets.booknow.css); </style>
<script async=’true’ src=’http://app.hotelrunner.com/assets/widgets.booknow.js'></script>
<script type=’text/javascript’ async=’true’>var hr={ key:’XXXXXXXX’, host:’//hotel-name.hotelrunner.com’, text:’booknow’, align:’Left’, valign:’Top’, background_color:’#ffffff’, locale:’en’ };</script>

Thank you so much in advance.