def checkemail(request):
  user = None
  if request.POST.has_key('email'):
    useremail = request.POST['email']
    result = {}
    user = User.objects.filter(useremail__iexact = useremail)
  if user:
    result = "1"
    result = simplejson.dumps(result)
  else:
    result = "0"
    result = simplejson.dumps(result)
  return HttpResponse(result, mimetype='application/javascript')

if(valid_email($('#reg-for-email').val())){
  var email = $('#reg-for-email').val();
  //这里把用户输入的EMAIL地址提交到后台数据库中去验证是否已存在。
  $.ajax({
    type:"POST" ,
    url:"/reg/checkemail",
    data:"email=" + email ,
    cache: false,
    success: function(result){
  if (result==1)
   {
    $("#reg-for-email-msg").removeClass("g-hide");
    $('#reg-for-email-msg').removeClass("msg-isok").addClass("msg-error").html("该邮箱已存在！");
    eok = true;
   }
   else
   {
    $("#reg-for-email-msg").addClass("g-hide");
    eok = false;
   }
    }
   })
}