Add a popup when clicked through to a 'plugin&

I managed (with the help of SO) to put a pulsing marker from a plugin to a map with the R leaflet package with the following script :

library(leaflet)
library(htmltools)
library(htmlwidgets)

# This tells htmlwidgets about our plugin name, version, and
# where to find the script. (There's also a stylesheet argument
# if the plugin comes with CSS files.)

esriPlugin <- htmlDependency("leaflet-icon-pulse",version = "1.0",
                             src = "realtimemap/",
                             script = "L.Icon.Pulse.js",stylesheet ="L.Icon.Pulse.css")

# A function that takes a plugin htmlDependency object and adds
# it to the map. This ensures that however or whenever the map
# gets rendered, the plugin will be loaded into the browser.
registerPlugin <- function(map, plugin) {
  map$dependencies <- c(map$dependencies, list(plugin))
  map
}

content <- paste(sep = "<br/>",
                 "<b><a> Homicide </a></b>",
                 "606 5th Ave. S",
                 "Ocean District, CA 98138"
)

leaflet() %>% addProviderTiles("CartoDB.DarkMatter") %>% setView(-122.4105513,37.78250256, zoom = 12) %>%
  addPopups(-122.41, 37.78, content,
            options = popupOptions(closeButton = TRUE)
  ) %>%
  registerPlugin(esriPlugin) %>%
  # Add your custom JS logic here. The `this` keyword
  # refers to the Leaflet (JS) map object.
  onRender("function(el,x) {
var pulsingIcon = L.icon.pulse({iconSize:[20,20],color:'red'});
var pulsingIcon2 = L.icon.pulse({iconSize:[15,15],color:'orange',heartbeat:2}); 
           var marker = L.marker([37.78,-122.41],{icon: pulsingIcon}).addTo(this);
           var marker = L.marker([37.75,-122.39],{icon: pulsingIcon2}).addTo(this);}")

But now, I would like to display some information if I click on those pulsing markers. Of course, I can't use addpopup nor addmarker from the leaflet package since I had to use an unorthodox way to add a marker from a plugin. How would you do that?

Ok, I found something. By doing this, it works!!!

  onRender("function(el,x) {
var pulsingIcon = L.icon.pulse({iconSize:[20,20],color:'red',heartbeat:0.5});
var pulsingIcon2 = L.icon.pulse({iconSize:[10,10],color:'orange',heartbeat:2});
           var marker = L.marker([37.78,-122.41],{icon: pulsingIcon}).bindPopup('<b>Hello world!</b><br>I am a popup.').openPopup().addTo(this);
           var marker = L.marker([37.75,-122.39],{icon: pulsingIcon2}).addTo(this);
           }")