HarmonyOS web组件和js交互

import webview from '@ohos.web.webview' 
@Entry 
@Component 
struct Index { 
  controller: webview.WebviewController = new webview.WebviewController() 
 
  messageHandlers = { 
    JSCallNativeHandler: (action: string, paramObj: string) => { 
      let jsonObject  = paramObj.length > 0 ? JSON.parse(paramObj) : '' 
      switch (action) { 
        case 'toA': 
          console.log(`${jsonObject.A}`) 
          break 
        case 'toB': 
          console.log(`${jsonObject.B}`) 
          break 
      } 
    } 
  } 
 
  build() { 
    Column() { 
      Web({ src: $rawfile('index.html'), controller: this.controller }) 
        .javaScriptAccess(true) 
        .domStorageAccess(true) 
        .javaScriptProxy({ 
          object: this.messageHandlers, 
          name: 'xxx', 
          methodList: ['JSCallNativeHandler'], 
          controller: this.controller 
        }) 
    } 
  } 
}