A method of controlling webpage behaviour on a web enabled device 3 in order to assist in, for example, collection of monitoring information, preserving session context, and improving security. The method includes monitoring a user interaction with a webpage (step 203), using a client side module 31 at the web enabled device 3, and determining whether predetermined conditions are satisfied (step 204). Where the predetermined conditions are satisfied the further steps below are carried out: capturing details concerning an intended result of said user interaction (step 205), using the client side module; at least temporarily preventing occurrence of the intended result of said user interaction using the client side module (step 206); carrying out additional processing (step 207) using the client side module; determining a controlled result (step 208), using the client side module, in dependence on said intended result and the additional processing; and causing the controlled result to occur (step 209). The additional processing might, for example, include collecting monitoring information, dynamically re-writing the URL to allow preservation of session context, or performing in checks or modifications to improve security.