what border length certified window.returnvalue property? (javascript)

is there border length controlling window.returnvalue (variant) modal?

i am job modal window controlling showmodaldialog() returning comma delimited string. after selecting organisation users, i am putting stringbuilder arrangement literal.

dim strreturn new stringbuilder
strreturn.append("<script type=""text/javascript"">window.returnvalue='")
dim strusers new stringbuilder
for any dtrow datarow getselectedusertable.rows
    strusers.tostring.length > 0 then
        strusers.append(",")
    finish if
    strusers.append(dtrow("userid"))
next
strreturn.append(strusers.tostring)
strreturn.append("';window.close();</script>")
litreturnjavascript.text = strreturn.tostring

so there border characters total window.returnvalue?