diff --git a/DrissionPage/_pages/chromium_base.py b/DrissionPage/_pages/chromium_base.py
index 6ef9b5c..9967f0f 100644
--- a/DrissionPage/_pages/chromium_base.py
+++ b/DrissionPage/_pages/chromium_base.py
@@ -694,7 +694,7 @@ class ChromiumBase(BasePage):
             if loc_ind_ele == 0:
                 loc_ind_ele = 1
             elif loc_ind_ele < 0:
-                loc_ind_ele = f'last()-{-loc_ind_ele}'
+                loc_ind_ele = f'last()+{loc_ind_ele}+1'
             xpath = f'xpath:(//*[name()="frame" or name()="iframe"])[{loc_ind_ele}]'
             r = self._ele(xpath, timeout=timeout)
 
diff --git a/DrissionPage/_pages/chromium_frame.py b/DrissionPage/_pages/chromium_frame.py
index ed03f8f..e224b23 100644
--- a/DrissionPage/_pages/chromium_frame.py
+++ b/DrissionPage/_pages/chromium_frame.py
@@ -58,7 +58,7 @@ class ChromiumFrame(ChromiumBase):
             self.doc_ele = ChromiumElement(self, obj_id=obj_id)
 
         self._rect = None
-        end_time = perf_counter() + 5
+        end_time = perf_counter() + 2
         while perf_counter() < end_time:
             if self.url not in (None, 'about:blank'):
                 break
diff --git a/DrissionPage/_pages/chromium_page.py b/DrissionPage/_pages/chromium_page.py
index 71b3f38..f7d4ac5 100644
--- a/DrissionPage/_pages/chromium_page.py
+++ b/DrissionPage/_pages/chromium_page.py
@@ -148,7 +148,7 @@ class ChromiumPage(ChromiumBase):
         if isinstance(id_or_num, str):
             return ChromiumTab(self, id_or_num)
         elif isinstance(id_or_num, int):
-            return ChromiumTab(self, self.tabs[id_or_num - 1 if id_or_num < 0 else id_or_num])
+            return ChromiumTab(self, self.tabs[id_or_num - 1 if id_or_num > 0 else id_or_num])
         elif id_or_num is None:
             return ChromiumTab(self, self.tab_id)
         elif isinstance(id_or_num, ChromiumTab):