diff --git a/articles/views.py b/articles/views.py
index 6c0f1d0..1a93bba 100644
--- a/articles/views.py
+++ b/articles/views.py
@@ -21,13 +21,21 @@ import controller
 @article_pages.route(".json")
 def index():
     v=request.values
-    if v.has_key("per_page"):
-        pp=int(v["per_page"])
-    else:
+    try:
+        if v.has_key("per_page"):
+            pp=int(v["per_page"])
+        else:
+            pp=20
+        if v.has_key("page"):
+            o=(int(v["page"])-1) *pp
+        else:
+            o=0
+    except ValueError:
         pp=20
-    if v.has_key("page"):
-        o=(int(v["page"])-1) *pp
-    else:
+        o=0
+    if not (isinstance(pp,int) and pp>0 and pp<10000):
+        pp=20
+    if not (isinstance(o,int) and o>=0 and o<100000):
         o=0
     articles=controller.get_all_page(pp,o)
     resp = jsonify(articles=articles)