function container(selector, test, stylesheet) {

  var tag = document.querySelectorAll(selector)
  var style = ''
  var count = 0

  for (var i=0; i<tag.length; i++) {

    var func = new Function(`return ${test}`)
    var attr = (selector+test).replace(/\W+/g, '')

    if (func.call(tag[i])) {

      tag[i].setAttribute(`data-${attr}`, count)

      var css = stylesheet.replace(/\$this/g, `[data-${attr}="${count}"]`)

      style += css

      count++

    } else {

      tag[i].setAttribute(`data-${attr}`, '')

    }

  }

  return style

}