Here is kerax:

  var lines: seq[kstring] = @[]
  
  proc createDom(): VNode =
    result = buildHtml(tdiv):
      button:
        text "Say hello!"
        proc onclick(ev: Event; n: VNode) =
          lines.add "Hello simulated universe"
      for x in lines:
        tdiv:
          text x
  
  setRenderer createDom

  fun main() {
    Kweb(port = 2734) {
        doc.body.new {
            button().text("Say hello!").on.click {
                println("Hello simulated universe")
            }
        }
    }
  }