Customize Shiny dropdown label thru Javascript

app.R

library(shiny)
indiv <- c('NA'=1,'STOCH'=2,'SMI'=3,'MACD'=4,'ROC'=5,'MFI'=6,'RSI'=7,'CCI'=8)

ui <- fluidPage(
	titlePanel("Customize dropdown label thru Javascript"),
	
	mainPanel(
	  fluidRow( selectInput(inputId="indik", label="Indicator", choices=indiv),
	    "click checkbox to reset the dropdown"
    ),
  	tags$script(
	  HTML(" window.onload = function() {
          var dlb = document.getElementById('indik').parentNode.parentNode.firstElementChild;  // Shiny's natural ordering
          var myspan = document.createElement('span'); 
          var lbl = document.createElement('LABEL'); lbl.textContent='Indicator'; lbl.className='control-label'; //lbl.htmlFor='indik-selectized';
          var cckbox = document.createElement('input'); cckbox.type='checkbox'; cckbox.id='iunsel'; cckbox.class='shinyjs-resettable shiny-bound-input'; cckbox.style.marginLeft='30px';
          myspan.appendChild(lbl); myspan.appendChild(cckbox); 
          dlb.parentNode.replaceChild(myspan, dlb);
       }
   	"))
  )
)
server <- function(input, output, session) {
  # see also session$onFlushed(function() { session$sendCustomMessage(type='jsCode', list(value=myScript)) }, once=TRUE)
  observeEvent(input$iunsel, {
    updateSelectInput(session, 'indik', selected=1 )
  })
}

shinyApp(ui = ui, server = server)