How to Split Comma Separated Values in SQL Server

Create FUNCTION [dbo].[Split_Function]
(@String varchar(MAX),@ImageNameByUser varchar(MAX)=null, @Delimiter char(1),@QuestionId bigint,@ID1 int)
returns @temptable TABLE (RightOptions varchar(MAX),NotInUse varchar(MAX),QuestionId bigint,QuestionOptionId bigint,RightAnswerId bigint)
as
begin
declare @idx int
declare @slice varchar(8000)
,@slice2 varchar(8000)
,@idx2 int
select @idx = 1
select @idx2 = 1
if len(@String)<1 or @String is null return
while @idx!= 0
begin
set @idx = charindex(@Delimiter,@String)
set @idx2 = charindex(@Delimiter,@ImageNameByUser)
if @idx!=0
set @slice = left(@String,@idx - 1)
else
set @slice = @String
if @idx2!=0
set @slice2 = left(@ImageNameByUser,@idx2 - 1)
else
set @slice2 = @ImageNameByUser
--If(IsNull(@ImageNameByUser,'@@')!='@@')
--if(len(@slice)>0 And len(@slice2)>0 )
--Else
if(len(@slice)>0)
BEGIN
SET @ID1=@ID1+1
declare @RightAnsId bigint
Select @RightAnsId=isnull(QuestionOptionId,0) from tblQuestionOption where OptionDetail = LTRIM(RTRIM(@slice)) And QuestionId=@QuestionId
insert into @temptable(RightOptions,NotInUse,QuestionId,QuestionOptionId,RightAnswerId)
values(LTRIM(RTRIM(@slice)),LTRIM(RTRIM(@slice2)),@QuestionId,@RightAnsId,@ID1)
END
set @String = right(@String,len(@String) - @idx)
if len(@String) = 0 break
set @ImageNameByUser = right(@ImageNameByUser,len(@ImageNameByUser) - @idx2)
if len(@ImageNameByUser) = 0 break
end
return
end