[content-invalid.html]
  [e.style['content'\] = "counter(foo, none)" should not set the property value]
    expected: FAIL

  [e.style['content'\] = "counters(foo, \\"\\", none)" should not set the property value]
    expected: FAIL

  [e.style['content'\] = "\\"z\\" counter(foo, none)" should not set the property value]
    expected: FAIL

  [e.style['content'\] = "\\"z\\" counters(foo, \\"\\", none)" should not set the property value]
    expected: FAIL

  [e.style['content'\] = "counter(foo, none) \\"z\\"" should not set the property value]
    expected: FAIL

  [e.style['content'\] = "counters(foo, \\"\\", none) \\"z\\"" should not set the property value]
    expected: FAIL