新手求教，这段代码是什么意思

<%
 if cstr(session("getcode"))<>cstr(Session("useryz")) then
 response.codePage =65001
 response.Charset="UTF-8"
 response.Write "<script language='javascript'>"
 response.Write "alert('验证码输入有误，请核对！');"
 response.Write "history.go(-1);"
 response.Write "</script>"
 response.End
 end if
 %>