# Getting Started With Compose for Web **The API is experimental, and breaking changes can be expected** ## Introduction In this tutorial, we will create a simple web UI application using the Compose UI framework. ## Prerequisites You need to have the following software installed before you begin: * JDK 11 or later * IntelliJ IDEA Community Edition or Ultimate Edition 2020.2 or later (you can use other editors, but for this tutorial we assume you are using IntelliJ IDEA) ## Creating a new project If you don't want to create the project manually, you can [download the example here](https://github.com/JetBrains/compose-jb/tree/master/examples/web-getting-started) The project wizard doesn't support Compose for web projects yet, so we need to perform the following steps: #### 1. Create a Kotlin Multiplatform project: - Select `Gradle` on the left menu - Tick `Kotlin DSL build script` - Tick `Kotlin/Multiplatform` ![](create-mpp.png) #### 2. Update `settings.gradle.kts`: ``` kotlin pluginManagement { repositories { gradlePluginPortal() maven("https://maven.pkg.jetbrains.space/public/p/compose/dev") } } ``` #### 3. Update `build.gradle.kts`: ```kotlin // Add compose gradle plugin plugins { kotlin("multiplatform") version "1.5.0" id("org.jetbrains.compose") version "0.0.0-web-dev-13" } // Add maven repositories repositories { mavenCentral() maven("https://maven.pkg.jetbrains.space/public/p/compose/dev") } // Enable JS(IR) target and add dependencies kotlin { js(IR) { browser() binaries.executable() } sourceSets { val jsMain by getting { dependencies { implementation(compose.web.core) implementation(compose.runtime) } } } } ``` #### 5. Add the following directories to the project: - src/jsMain/kotlin - src/jsMain/resources #### 6. Add the `index.html` file to the `resources`: ```html Sample
``` #### 7. Add the `Main.kt` file: ```kotlin fun main() { var count: Int by mutableStateOf(0) renderComposable(rootElementId = "root") { Div(style = { padding(25.px) }) { Button(attrs = { onClick { count -= 1 } }) { Text("-") } Span(style = { padding(15.px) }) { Text("$count") } Button(attrs = { onClick { count += 1 } }) { Text("+") } } } } ``` In case you see an error: `Type 'MutableState' has no method 'getValue(Nothing?, KProperty<*>)'...` or `Type 'MutableState' has no method 'setValue(Nothing?, KProperty<*>, Int)'...`, please add the imports: ```kotlin import androidx.compose.runtime.getValue import androidx.compose.runtime.setValue ``` ## Running the project Use the command line to run: ```shell ./gradlew jsBrowserRun ``` Or run it from the IDE: ![](run_project.png) The browser will open `localhost:8080`: ![](run_result.png)