https security is compromised - error message

I'm calling a REST Service from a web part using JavaScript. My SharePoint site is running under HTTPS, my service is running under HTTP. When I run my page I'm getting the [SEC7111 https security is compromised by http://server/servicename.

I'm unable to make changes to the browser on the users pc, is there any way in code I can correct this or should I get the service to change from HTTP to HTTPS?  (its an internal REST Service I'm calling, not an outside service)