This is a common pattern for embedding scripts, so the browser will use the same protocol as the parent page loading the element (http or https), avoiding issue

This is a common pattern for embedding scripts, so the browser will use the same protocol as the parent page loading the element (http or https), avoiding issues with embedding insecure content in a secure page. I thought it worked for iframe elements too - but I guess it's not consistently supported? It works for me in Chrome on Win7. Edit - more info about "Protocol Relative URLs": http://stackoverflow.com/questions/550038/is-it-valid-to-replace-http-with-in-a-script-src-http http://stackoverflow.com/questions/550038/is-it-valid-to-rep...