(PHP 8 >= 8.4.0)
mb_trim — Strip whitespace (or other characters) from the beginning and end of a string
   Performs a multi-byte safe trim() operation,
   and returns a string with whitespace stripped from the
   beginning and end of string.
   Without the second parameter,
   mb_trim() will strip these characters:
  
" " (Unicode U+0020), an ordinary space.
     
    "\t" (Unicode U+0009), a tab.
     
    "\n" (Unicode U+000A), a new line (line feed).
     
    "\r" (Unicode U+000D), a carriage return.
     
    "\0" (Unicode U+0000), the NUL-byte.
     
    "\v" (Unicode U+000B), a vertical tab.
     
    "\f" (Unicode U+000C), a form feed.
     
    "\u00A0" (Unicode U+00A0), a NO-BREAK SPACE.
     
    "\u1680" (Unicode U+1680), a OGHAM SPACE MARK.
     
    "\u2000" (Unicode U+2000), a EN QUAD.
     
    "\u2001" (Unicode U+2001), a EM QUAD.
     
    "\u2002" (Unicode U+2002), a EN SPACE.
     
    "\u2003" (Unicode U+2003), a EM SPACE.
     
    "\u2004" (Unicode U+2004), a THREE-PER-EM SPACE.
     
    "\u2005" (Unicode U+2005), a FOUR-PER-EM SPACE.
     
    "\u2006" (Unicode U+2006), a SIX-PER-EM SPACE.
     
    "\u2007" (Unicode U+2007), a FIGURE SPACE.
     
    "\u2008" (Unicode U+2008), a PUNCTUATION SPACE.
     
    "\u2009" (Unicode U+2009), a THIN SPACE.
     
    "\u200A" (Unicode U+200A), a HAIR SPACE.
     
    "\u2028" (Unicode U+2028), a LINE SEPARATOR.
     
    "\u2029" (Unicode U+2029), a PARAGRAPH SEPARATOR.
     
    "\u202F" (Unicode U+202F), a NARROW NO-BREAK SPACE.
     
    "\u205F" (Unicode U+205F), a MEDIUM MATHEMATICAL SPACE.
     
    "\u3000" (Unicode U+3000), a IDEOGRAPHIC SPACE.
     
    "\u0085" (Unicode U+0085), a NEXT LINE (NEL).
     
    "\u180E" (Unicode U+180E), a MONGOLIAN VOWEL SEPARATOR.
     
    stringcharacterscharacters parameter.
  Simply list all characters that need to be stripped.
 
    encodingIl parametro encoding 
è la codifica dei caratteri. Se è omesso, verrà utilizzata la 
codifica interna.
The trimmed string.
