function checkEmail()
   {  

      if (document.request.Email_address.value.length ==0)
         {
         alert("Please enter an email address.")
         return false
         }
      if (document.request.Email_address.value.length >0)
      {
      i=document.request.Email_address.value.indexOf("@")
      j=document.request.Email_address.value.indexOf(".",i)
      k=document.request.Email_address.value.indexOf(",")
      l=document.request.Email_address.value.indexOf(" ")
      m=document.request.Email_address.value.indexOf(".@")
      n=document.request.Email_address.value.indexOf("@.")
      o=document.request.Email_address.value.indexOf("..")
      q=document.request.Email_address.value.indexOf(".")
      r=document.request.Email_address.value.lastIndexOf(".")+1
      len=document.request.Email_address.value.length

      if ((i>0) && (j>(1+1)) && (k==-1) && (l==-1) && (m==-1) && (n==-1) && (o==-1) && (q>0) &&
      (len-r >=2) && (len-r<=3))
         {
         }
      else 
         {
         alert("Please enter an exact email address.\n" +
         document.request.Email_address.value + " is invalid.")
         return false
         }
      }
   }