code: function vendorPropName( name ) {
  
    // shortcut for names that are not vendor prefixed
    // when name already have '-' as first char, don't prefix
    if ( name in emptyStyle || name[0] == '-') return
  
    // check for vendor prefixed names
    var preName, capName = capitalize(name);
    var i = cssPrefixes.length;
  
    while ( i-- ) {
      preName = cssPrefixes[ i ] + capName;
      if ( preName in emptyStyle ) return preName
    }
  }
docs: return a css property mapped to a potentially vendor prefixed property