Error: access is denied with code 0

this could be cross - domain calls in javascript

try in chrome without security

Repeater in ajax tab component

kept on going out of bounds
tabcontrol scrollbars did not help;likewise asp:panel with scrollbars

at the end i just added div inside tabpanel

Asp.net updatepanel

I kinda agree with a comment I found that updatepanels are useless if they lose css formatting on postbacks 

calendar for asp.net

had so many problems with calendar extender finally used this

ajax toolkit

I was creating calendar controls on the fly and this was producing bizarre javascript errors. The answer -
I was using plain scriptmanager instead of
 <asp:ToolkitScriptManager ID="Scriptmanager1" runat="server"></asp:ToolkitScriptManager>