   #Form
   form: {category: 'form'}
   input: {category: 'form'}
-  textarea: {category: 'form'}
+  textarea: {category: 'form', content: 'optional'}
   label: {category: 'form'}
   button: {category: 'form'}
   select: {category: 'form'}

  datalist: {category: 'form'}
  keygen: {category: 'form'}
  output: {category: 'form'}
  progress: {category: 'form'}
  meter: {category: 'form'}
  fieldset: {category: 'form'}
  legend: {category: 'form'}

  #Embedded
  img: {category: 'embedded'}
  iframe: {category: 'embedded'}
  embed: {category: 'embedded'}
  object: {category: 'embedded'}
  param: {category: 'embedded'}

  dialog: {category: 'other'}
  noscript: {category: 'other'}
  template: {category: 'other'}
  canvas: {category: 'other', content: 'optional'}
  svg: {category: 'other'}
  frameset: {category: 'other'}
}
