# Setup Every UI5 application has an `index.html` that bootstraps the framework, picks a theme, loads a UI5 version and so on. With abap2UI5 you don't maintain that file by hand — the framework generates it on every page load. To change what ends up in it, implement the `z2ui5_if_ui5_exit` interface in your own ABAP class: ```abap CLASS zcl_a2ui5_user_exit DEFINITION PUBLIC. PUBLIC SECTION. INTERFACES z2ui5_if_ui5_exit. ENDCLASS. CLASS zcl_a2ui5_user_exit IMPLEMENTATION. METHOD z2ui5_if_ui5_exit~set_config_http_get. " your configuration goes here ENDMETHOD. ENDCLASS. ``` `set_config_http_get` is called once per page request — i.e. when the browser asks for the HTML shell. The changing parameter `cs_config` holds every value that ends up in the generated `index.html`. ## What You Can Configure | Page | Field on `cs_config` | Affects in `index.html` | |-------------------------------------------------------------------|------------------------------|-------------------------| | [Theme](/configuration/setup/theme) | `theme` | `data-sap-ui-theme` on the bootstrap script | | [Bootstrapping](/configuration/setup/ui5_bootstrapping) | `src` | `src` of the bootstrap script (UI5 version + delivery channel) | | [Bootstrap Attributes](/configuration/setup/bootstrap_attributes) | `t_add_config` | Additional `data-sap-ui-*` attributes | | [Style / CSS](/configuration/setup/style_css) | `styles_css` | Inline `