1# JS UI Framework<a name="EN-US_TOPIC_0000001076213364"></a> 2 3 4- [Introduction](#section15701932113019) 5- [Directory Structure](#section1791423143211) 6- [When to Use](#section171384529150) 7- [Available Components](#section271831717166) 8- [Repositories Involved](#section1447164910172) 9 10## Introduction<a name="section15701932113019"></a> 11 12The OpenHarmony JS UI framework provides basic, container, and canvas UI components and standard CSS animation capabilities. It supports the web-development-like programming paradigm. 13 14- **Web-development-like paradigm** 15 16 The JS UI framework supports languages that are similar to those for web development, such as HTML and CSS. You can use them to describe the page layout and style, and use JavaScript \(conforming to the ECMAScript specification\) for page behavior. This paradigm allows you to avoid code for UI state switching. The view configuration information is intuitive. 17 18 19**Figure 1** Framework architecture<a name="fig2606133765017"></a> 20 21 22The JS UI framework consists of the application, framework, engine, and porting layers. 23 24- **Application** 25 26 Contains apps with Feature Abilities \(FAs\) developed with the JS UI framework. The FA app in this document refers to the app with FAs developed using JavaScript. 27 28- **Framework** 29 30 Parses UI pages and provides the Model-View-ViewModel \(MVVM\), page routing, custom components and more for front end development. 31 32- **Engine** 33 34 Accomplishes animation parsing, Document Object Model \(DOM\) building, layout computing, rendering command building and drawing, and event management. 35 36- **Porting Layer** 37 38 Abstracts the platform layer to provide abstract interfaces to connect to the platform. For example, event interconnection, rendering pipeline interconnection, and lifecycle interconnection. 39 40 41## Directory Structure<a name="section1791423143211"></a> 42 43The source code of the framework is stored in **/foundation/arkui/ace\_engine**. The following shows the directory structure. 44 45``` 46/foundation/arkui/ace_engine 47├── adapter # Platform adaptation code 48│ ├── common 49│ └── ohos 50├── frameworks # Framework code 51│ ├── base # Basic libraries 52│ ├── bridge # Bridging layer for frontend and backend components 53│ └── core # Core components 54``` 55 56## When to Use<a name="section171384529150"></a> 57 58JS UI framework provides various UI components with rich functionalities and style definitions. You can use and reuse any component anywhere as needed. You can customize new components by combining existing ones to simplify development. 59 60## Available Components<a name="section271831717166"></a> 61 62**Table 1** Components provided by the framework 63 64<a name="table2347172925617"></a> 65<table><thead align="left"><tr id="row5347429155610"><th class="cellrowborder" valign="top" width="28.64%" id="mcps1.2.3.1.1"><p id="p1347102910567"><a name="p1347102910567"></a><a name="p1347102910567"></a>Type</p> 66</th> 67<th class="cellrowborder" valign="top" width="71.36%" id="mcps1.2.3.1.2"><p id="p83475294565"><a name="p83475294565"></a><a name="p83475294565"></a>Components</p> 68</th> 69</tr> 70</thead> 71<tbody><tr id="row15347122918562"><td class="cellrowborder" valign="top" width="28.64%" headers="mcps1.2.3.1.1 "><p id="p679795614335"><a name="p679795614335"></a><a name="p679795614335"></a>Basic</p> 72</td> 73<td class="cellrowborder" valign="top" width="71.36%" headers="mcps1.2.3.1.2 "><p id="p88813982011"><a name="p88813982011"></a><a name="p88813982011"></a>button, text, input, label, image, progress, rating, span, marquee, image-animator, divider, menu, chart, option, picker, picker-view, piece, qrcode, select, slider, switch, toolbar, toolbar-item, toggle</p> 74</td> 75</tr> 76<tr id="row1973535793115"><td class="cellrowborder" valign="top" width="28.64%" headers="mcps1.2.3.1.1 "><p id="p8735195713313"><a name="p8735195713313"></a><a name="p8735195713313"></a>Container</p> 77</td> 78<td class="cellrowborder" valign="top" width="71.36%" headers="mcps1.2.3.1.2 "><p id="p1268024618208"><a name="p1268024618208"></a><a name="p1268024618208"></a>div, list, list-item, list-item-group, stack, swiper, tabs, tab-bar, tab-content, refresh, dialog, badge, panel, popup, stepper, stepper-item</p> 79</td> 80</tr> 81<tr id="row1792218915320"><td class="cellrowborder" valign="top" width="28.64%" headers="mcps1.2.3.1.1 "><p id="p692289163220"><a name="p692289163220"></a><a name="p692289163220"></a>Canvas</p> 82</td> 83<td class="cellrowborder" valign="top" width="71.36%" headers="mcps1.2.3.1.2 "><p id="p199228910327"><a name="p199228910327"></a><a name="p199228910327"></a>canvas</p> 84</td> 85</tr> 86<tr id="row837615526208"><td class="cellrowborder" valign="top" width="28.64%" headers="mcps1.2.3.1.1 "><p id="p4377752152016"><a name="p4377752152016"></a><a name="p4377752152016"></a>Grid</p> 87</td> 88<td class="cellrowborder" valign="top" width="71.36%" headers="mcps1.2.3.1.2 "><p id="p17377185222019"><a name="p17377185222019"></a><a name="p17377185222019"></a>grid-container, grid-row, grid-col</p> 89</td> 90</tr> 91</tbody> 92</table> 93 94## Repositories Involved<a name="section1447164910172"></a> 95 96JS UI framework 97 98**arkui\_ace\_engine** 99 100ace\_engine\_lite 101 102arkui\_napi 103 104
