Advanced FORM object

HTML5 specifies a new attribute called "placeholder". The value of this attribute is visible in gray in a textfield, if no value has been entered yet.

The form plugin should allow using this attribute.

Example:

lib.SearchBox = FORM_INT
 lib.SearchBox {
   action = 19
   method = post

10 = TEXTLINE
   10 {
     name = tx_indexedsearch[sword]
     placeholder = Start searching...
     label {
       value = Search:
     }
   }
 }