crm 2011 textbox onFocus event

Hi Experts,

Is it possible to use crm 2011 textfield onfocus event.

Actually i need a popup when ever anyone focus on a text field within crm 2011.

I have designed the popup and now it is showing in textchange event of the crm 2011.

So can you plz help to add onFocus event for crm 2011 text fields.

Thanking You