vbs-求两个字符的公共字符串

Option Explicit

Function findPublicStr ( str1 ,  str2  )
 Dim shortStr, longStr
 
  Dim maxlength
  If len(str1) > len(str2)Then
   maxlength = len(str2)
   shortStr = str2
   longStr = str1
  
   else
    maxlength = len(str1)
    longStr  = str2
    shortStr = str1
  End If
 
  Dim i, j
 Dim str , pubstr, temp, result
 temp = 0
  For i = 1 to maxlength step 1
   For j =  maxlength  to 1 step -1
    str =mid (shortStr, i, j)
 
    If instr(longStr, str) >0  Then
     pubstr = str
 
     If len(pubstr) > temp Then
      result  = pubstr
      temp =  len(pubstr)
     End If    
 
    End If 
 
   Next
 
  Next
 
 findPublicStr = result

End Function

msgbox findPublicStr( "2341234", "245412")