info icon next to label of a selectInput in Shiny - html

Question

I'm developing a shiny app and I want to add an "infobox" next to a selectInput(). Basically I want to add a small "info" icon to the selectInput() label and when a user move the mouse hover the info icon, a box with some text appears. I've found here on stackedoverflow a solution with tags$span and tags$i and if I add only text it works fine, but if I want to add an html link, or simply another tags (like tags$strong), it doesn't work. Here a reproducible example.
library(shiny)
shinyApp(
ui = fluidPage(
br(),
selectInput("works",
label = tags$span(
"This works",
tags$i(
class = "glyphicon glyphicon-info-sign",
style = "color:#0072B2;",
title = "Further information "
)),
choices = c("a","b")),
selectInput("notwork",
label = tags$span(
"This not works",
tags$i(
class = "glyphicon glyphicon-info-sign",
style = "color:#0072B2;",
title = list("Further information ",
tags$a(href = "https://www.google.com", "here", .noWS = "after"))
)),
choices = c("a","b")),
selectInput("notwork2",
label = tags$span(
"Neither this",
tags$i(
class = "glyphicon glyphicon-info-sign",
style = "color:#0072B2;",
title = p("Further information ",
strong("here"))
)),
choices = c("a","b")),
),
server = function(input, output) {
}
)
It looks I can't pass any other html tags to that value.

Answer 1

You try to put HTML in a normal HTML title attribute, which is never supported. what you need is some sort of Tooltip. You can use bsButton in combination with bsPopover from the ShinyBS package. I did not bother for the styling, but I am pretty sure you can get it done from here.
library(shiny)
library(ShinyBS)
shinyApp(
ui = fluidPage(
br(),
selectInput("works",
label = tags$span(
"This works",
tags$i(
class = "glyphicon glyphicon-info-sign",
style = "color:#0072B2;",
title = "Further information "
)),
choices = c("a","b")),
selectInput("worksnow",
label = tags$span("This works now too", bsButton("thisworks", label = "", icon = icon("info"), style = "info", size = "extra-small")),
choices = c("a","b")
),
bsPopover(
id = "thisworks",
title = "More information",
content = paste0(
"Any HTML can be here ",
a("ShinyBS", href = "https://ebailey78.github.io/shinyBS/index.html", target="_blank")
),
placement = "right",
trigger = "hover",
options = list(container = "body")
)
),
server = function(input, output) {
}
)