title: Display the selectInput value in a R shiny widget box
body: <p>Please run the R shiny script below, I wish to display the selectInput value in the third selectInput option in the infoBox widget and replicate the same functionality for all the tabs below. Currently it is hard coded, the script has been written using shiny modules, so kindly check. Attaching the snapshot for reference, please help.</p>
  
  <pre><code>candyData &lt;- read.table(
  text = "
  Brand       Candy           value
  Nestle      100Grand        Choc1
  Netle       Butterfinger    Choc2
  Nestle      Crunch          Choc2
  Hershey's   KitKat          Choc4
  Hershey's   Reeses          Choc3
  Hershey's   Mounds          Choc2
  Mars        Snickers        Choc5
  Nestle      100Grand        Choc3
  Nestle      Crunch          Choc4
  Hershey's   KitKat          Choc5
  Hershey's   Reeses          Choc2
  Hershey's   Mounds          Choc1
  Mars        Twix            Choc3
  Mars        Vaid            Choc2",
  header = TRUE,
  stringsAsFactors = FALSE)
  library(shiny)
  library(shinydashboard)
  submenuUI &lt;- function(id) {
  ns &lt;- NS(id)
  tagList(
  box(title = "Data", status = "primary", solidHeader = T, width = 12,
      fluidPage(
        fluidRow(
  
          column(2,offset = 0, style='padding:1px;',
  
  selectInput(ns("Select1"),"select1",unique(candyData$Brand))),
          column(2,offset = 0,
  
  style='padding:1px;',selectInput(ns("Select2"),"select2",choices = NULL)),
          column(2, offset = 0,
  
  style='padding:1px;',selectInput(ns("Select3"),"select3",choices=NULL ))
        ))
      ),
  infoBox("value1", 5)
  )}
  # submenu &lt;- function(input,output,session){}
  submenuServ &lt;- function(input, output, session){
  observeEvent(input$Select1,{
  updateSelectInput(session,'Select2',
  
  
  choices=unique(candyData$Candy[candyData$Brand==input$Select1]))
  })
  observeEvent(input$Select2,{
  updateSelectInput(session,'Select3',
  
  
  choices=unique(candyData$value[candyData$Brand==input$Select1 &amp;
  
  candyData$Candy==input$Select2]))
  })}
  ui &lt;- dashboardPage(
  dashboardHeader(),
  dashboardSidebar(
  sidebarMenu(
    shinyjs::useShinyjs(),
    id = "tabs",
    menuItem("Charts", icon = icon("bar-chart-o"),
             shinyjs::hidden(menuSubItem("dummy", tabName = "dummy")),
             menuSubItem("Sub-item 1", tabName = "subitem1"),
             menuSubItem("Sub-item 2", tabName = "subitem2"),
             menuSubItem("Sub-item 3", tabName = "subitem3")
    ))),
    dashboardBody(
    tabItems(tabItem("dummy"),
           tabItem("subitem1", submenuUI('submenu1')),
           tabItem("subitem2", submenuUI('submenu2')),
           tabItem("subitem3", submenuUI('submenu3')))))
   server &lt;- function(input, output,session) {
  
   callModule(submenuServ,"submenu1")
   callModule(submenuServ,"submenu2")
   callModule(submenuServ,"submenu3")
   }
   shinyApp(ui = ui, server = server)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/WVfBT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WVfBT.png" alt="BoxInput Value"></a></p>