EMBEDDED WEB PAGES IN WEB CLIENT using iframe was introduced in Patch 5 of FSM update 6. However this MetrixBrowser implementation on the Webclient is not consistent with the behavior from the smart client.
In smart client the iframe url is able to resolve the substitution variable however the webclient is unable to do it. See example below
Ex using the URL -> https://www.google.com/webhp?igu=1&q={{address.geocode_lat}}&output=svembed on the address screen we see that the webclient is unable to resolve the substitution variable {{address.geocode_lat}} like the smart client
Smart client – The URL is able to substitute {{address.geocode_lat}} with the value of address.latitude which is 43.0333862305
Webclient - The URL is unable to substitute {{address.geocode_lat}} with the value of address.latitude which is 43.0333862305 and just passes the tag as it is.