net APPLIATION dashboard, i need to provide help icon on the screen. For that i have few option as follows
I can use AJAX modal popup and register usercontrol having help content and show it on modal popup control on click of help button
I can use javascript buble tooltip for help on mouse over/enter of help icon.
Can you suggest me right approach
There is never a "right" or "wrong" approach, certainly not in a clear-cut fashion. What I personally would do is use jQuery to provide a client-side modal (or modeless) dialog and populate the dialog via AJAX. In this regard I could have a dynamic help page loading help from a database and I wouldn't have to reinvent the wheel on each page so to speak. jQuery.UI has a decent modal dialog that would work well in this situation so long as you coded up the rest to pull the content.
I would also go with a jQuery/JavaScript type popup, I think a correct approach might be to only load the content when its required, ie on icon rollover or on click to reduce overhead.