Merge pull request #3256 from VisualSJ/develop_webview

Fixed a bug about webview goback

Author: pandamicro

Diff for: extensions/ccui/uiwidgets/UIWebView.js

@@ -101,7 +101,11 @@ ccui.WebView = ccui.Widget.extend(/** @lends ccui.WebView# */{
             if(iframe){
                 var win = iframe.contentWindow;
                 if(win && win.location)
-                    win.history.back.call(win);
+                    try {
+                        win.history.back.call(win);
+                    } catch (error) {
+                        win.history.back();
+                    }
             }
         }catch(err){
             cc.log(err);
@@ -119,7 +123,11 @@ ccui.WebView = ccui.Widget.extend(/** @lends ccui.WebView# */{
             if(iframe){
                 var win = iframe.contentWindow;
                 if(win && win.location)
-                    win.history.forward.call(win);
+                    try {
+                        win.history.forward.call(win);
+                    } catch (error) {
+                        win.history.forward();
+                    }
             }
         }catch(err){
             cc.log(err);