Google chart won't load when the site is online

I have a little web app that contains a form and a chart (Google Chart) that populates with the information the user writes in the fields of the form. It works just fine when run on the localhost but when I put it online (000webhost, free account) the chart won't show. In fact the whole div that contains the chart is empty.

this is how it is displayed on the localhost

this is how it looks online