quals(element.getAttribute("mode"), "not-a-valid-value");
}, document.title + ", getter, invalid value");

const enumerationMap = [
  [ "normal", "NORMAL" ],
  [ "multiply", "MULTIPLY" ],
  [ "screen", "SCREEN" ],
  [ "darken", "DARKEN" ],
  [ "lighten", "LIGHTEN" ],
  [ "overlay", "OVERLAY" ],
  [ "color-dodge", "COLOR_DODGE" ],
  [ "color-burn", "COLOR_BURN" ],
  [ "hard-light", "HARD_LIGHT" ],
  [ "soft-light", "SOFT_LIGHT" ],
  [ "difference", "DIFFERENCE" ],
  [ "exclusion", "EXCLUSION" ],
  [ "hue", "