# Getting started with the Compose HTML library
In this tutorial, we will create a simple web UI application using the Compose HTML Library.
## 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
You can create the project by [downloading the template here ](https://github.com/JetBrains/compose-multiplatform-html-library-template ).
If you want to create the project manually, perform the following steps:
#### 1. Create a Kotlin Multiplatform project:
- Select `Gradle` on the left menu
- Tick `Kotlin DSL build script`
- Tick `Kotlin/Multiplatform`
< img alt = "" src = "create-mpp.png" height = "500" / >
#### 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 "1.8.20"
id("org.jetbrains.compose") version "1.4.1"
}
// Add maven repositories
repositories {
mavenCentral()
maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
google()
}
// Enable JS(IR) target and add dependencies
kotlin {
js(IR) {
browser()
binaries.executable()
}
sourceSets {
val jsMain by getting {
dependencies {
implementation(compose.html.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
<!DOCTYPE html>
< html lang = "en" >
< head >
< meta charset = "UTF-8" >
< title > Sample< / title >
< / head >
< body >
< div id = "root" > < / div >
< script src = "REPLACE_WITH_YOUR_MODULE_NAME.js" > < / script >
< / body >
< / html >
```
#### 7. Add the `Main.kt` file to the `kotlin`:
```kotlin
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.getValue
import androidx.compose.runtime.setValue
import androidx.compose.runtime.Composable
import org.jetbrains.compose.web.attributes.*
import org.jetbrains.compose.web.css.*
import org.jetbrains.compose.web.dom.*
import org.jetbrains.compose.web.renderComposable
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("+")
}
}
}
}
```
## Running the project
Use the command line to run:
```shell
./gradlew jsBrowserRun
```
Instead of manually compiling and executing a Kotlin/JS project every time you want to see the changes you made, you can use the continuous compilation mode:
```shell
./gradlew jsBrowserRun --continuous
```
Or run it from the IDE:
< img alt = "" src = "run_project.png" height = "500" / >
The browser will open `localhost:8080` :
< img alt = "" src = "run_result.png" height = "500" / >
## Common issues when running the project
#### [webpack-cli] Unable to load '@webpack-cli/serve' command
https://youtrack.jetbrains.com/issue/KT-49124
```
[webpack-cli] Unable to load '@webpack-cli/serve' command
[webpack-cli] TypeError: options.forEach is not a function
...
```
There is a temporary workaround:
```
In build.gradle.kts:
// a temporary workaround for a bug in jsRun invocation - see https://youtrack.jetbrains.com/issue/KT-48273
afterEvaluate {
rootProject.extensions.configure< org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension > {
versions.webpackDevServer.version = "4.0.0"
versions.webpackCli.version = "4.9.0"
}
}
```
