I'm not sure what you are getting at here.
Do you have a popup window with the OnBlur event on and a lower window below it with the form on? If so your onBlur event will always happen as soon as you try to change the focus to the lower window and you will get yourself stuck in a loop.
I imagine that it is the same thing even if it is on a single window. As soon as you try and take the focus from the main body into a form element the OnBlur puts it right back and again you are stuck in a loop.
Your best bet is to create the Blur / Focus relationship in the loop that you want it - so when the user tries to change the focus from the window then put it in the text box. Once the text box is filled in change it to the next item etc.