Dynamic code generation and coordination techniques are provided for display of dynamic markup documents including script code. A code generation process is not only guided by deferral of code preparation stages and sub-stages, but also informed by various information levels possessed concerning the code itself, either through interpretation or observation of execution, to not only generate modified code, but also to generate alternative code for alternative situations (e.g., generating different loop bodies that can thereafter be readily swapped in or out depending on a given function call by the browser application). A multi-core architecture further improves user experience by asymmetrically ensuring web site presentation and functionality is prioritized for the user experience.