null length of cstrToNimstr using Karax

null_length_js_karax.nim

include karax/prelude

var
  viewmain = true
  viewsub = false

proc subRender: VNode =
  proc subcb =
    viewmain = true
    viewsub = false
    let
      usernode = getVNodeById("ureg")
      passnode = getVNodeById("preg")
    echo usernode.text
    echo passnode.text

  result = buildHtml tdiv():
    p: text "Sub page"
    input(id="ureg", `type`="text")
    input(id="preg", `type`="password")
    button(onclick = subcb): text "View main"

proc mainRender: VNode =
  proc maincb =
    viewsub = true
    viewmain = false
    let
      usernode = getVNodeById("user")
      passnode = getVNodeById("pass")
    echo usernode.text
    echo passnode.text
      
  if viewmain:
    viewmain = false
    result = buildHtml tdiv():
      p: text "Main page"
      button(onclick = proc() =
        viewsub = true
        viewmain = false
      ): text "View sub"
  elif viewsub:
    result = subRender()

setRenderer mainRender