How to Eliminate the Warning "This Page Contains Both Secure and Nonsecure Items"

In Internet Explorer click Tools
Select a Zone (select appropriate zone from where you're working i.e. Internet)
halfway down, locate "Display Mixed Content" under the Misc section
Change from Prompt to Enable
click OK

This can be addressed through a Group Policy Object as well.
User Configuration
Administrative Templates
Windows Components
Internet Explorer
Internet Control Panel
Security Page
Internet Zone
in the right Pane, select Display Mixed Content
set GPO to Enabled
in the drop down list, select Enabled