Remove Special Character from XML string using SQL Server

Create a function in MSSQL to remove all special characters from XML.
ALTER FUNCTION [dbo].[RemoveSpChar]
(
– Add the parameters for the function here
@sInput varchar(MAX)=”
)
RETURNS varchar(MAX)
AS
BEGIN
– Declare the return variable here
DECLARE @sOutput Varchar(MAX),
@iIndex int,
@iLength int,
@sChar varchar(1),
@iASCII int,
@iLen int,
@iRem int
set @sInput= ltrim(rtrim(@sInput))
set @iLength = len(@sInput)
set @iIndex =1
set @sOutput=”
while @iIndex <= @iLength
begin
set @sChar=substring(@sInput,@iIndex,1)
set @iASCII=ascii(@sChar)
if ((@iASCII>=48 and @iASCII<=57) or (@iASCII>=65 [...]