period=14
plusDM = highest[period](high)
minusDM =lowest[period](low)

IF plusDM > minusDM THEN
minusDM = 0
ENDIF

IF plusDM < minusDM THEN
plusDM = 0
ENDIF

IF plusDM = minusDM THEN
plusDM = 0
minusDM = 0
ENDIF

REM Let's compute the directional indicators
plusDm =  highest[period](high)
minusDm = lowest[period](low)

DX = ABS((lowest[period](low)-close)/lowest[period](low)-lowest[period](low))*-100
DX = williams [period](DX)
return dx as "Williams R percent", -20 as "-20 level", -80 as "-80 level"