# Bootstrap Attributes The UI5 bootstrap script tag in `index.html` accepts a long list of `data-sap-ui-*` attributes — they control asynchronous loading, the compatibility version, clickjacking protection, locale, preloaded libraries and many more. abap2UI5 already sets sensible defaults: ```html ``` ## Add or Override Attributes To add an attribute — or override one of the defaults — append a row to `cs_config-t_add_config`. Each row contributes one `name='value'` pair to the script tag: ```abap METHOD z2ui5_if_ui5_exit~set_config_http_get. cs_config-t_add_config = VALUE #( ( n = `data-sap-ui-libs` v = `sap.m,sap.ui.table` ) ( n = `data-sap-ui-language` v = `en` ) ( n = `data-sap-ui-frameOptions` v = `allow` ) ( n = `data-sap-ui-preload` v = `async` ) ). ENDMETHOD. ``` ## Useful Attributes | Attribute | Purpose | |---------------------------------|---------| | `data-sap-ui-libs` | Comma-separated list of UI5 libraries to preload (e.g. `sap.m,sap.ui.table`). Trade load time against startup speed. | | `data-sap-ui-language` | UI5 locale; overrides the browser language. See [Language](/configuration/setup/logon_language). | | `data-sap-ui-compatVersion` | Compatibility version, controls UI5 behavior for deprecated APIs. abap2UI5 defaults to `edge`. | | `data-sap-ui-async` | Asynchronous module loading. Default `true` — only change for legacy reasons. | | `data-sap-ui-preload` | Module preloading strategy: `async`, `sync` or empty (off). | | `data-sap-ui-frameOptions` | Clickjacking protection: `trusted`, `allow`, `deny`. Default `trusted`. | | `data-sap-ui-allowlistService` | Endpoint for the URL allowlist service. | | `data-sap-ui-bindingSyntax` | Binding syntax: `complex` (default) or `simple`. abap2UI5 expressions require `complex`. | | `data-sap-ui-resourceroots` | Additional resource roots for custom libraries. | | `data-sap-ui-xx-componentpreload` | Component-preload strategy for very large apps. | Attributes set by abap2UI5 by default can be overridden — a row with the same name wins over the framework default. ## See Also - Official UI5 [configuration options and URL parameters reference](https://sapui5.hana.ondemand.com/#/topic/91f2d03b6f4d1014b6dd926db0e91070) — the authoritative list of every supported attribute. - [Bootstrapping](/configuration/setup/ui5_bootstrapping) — how to change the bootstrap script source.