How to set the focus to a child window without refreshing it?

Recently I had a requirement, in my web page which contain four links, each link open a popup window. I am using a common JavaScript function to open popup window as given below,

Now when click on a link, it opens a popup window, which contain a data entry form, I entered some information into that form. Then I need to review other information, from other popup window, so I go back to the main window, click on another link, a new popup window get open which contain the information I need to review. I get the information and close this popup window, so now I am on the main window, then again I click on the link for that data entry form, so the popup window comes up but I lost the information that I have entered, that's because I am relodiing the popup window once again. So here the question arise,

1. Is their any way, I can check out the if popup window is already open from parent window, without having the object of popup window just by the name?
2. If the popup window is already open how can I just set the focus to it, rather then reloading it?
3. Can I refer a popup window from a parent window, even after refreshing the parent window?

And finally I got the solution for all the questions. Make some changes in the function as given below and it start working the way I want it,
















Let us see how it works,

• When attempt to open the window again with the same name in the second parameter of the windows open method, you will to get the windows handle. If the window is already open, it will return the handle of the opened window or it will open a new window and return it's handle
• The first parameter (the url) is passed as an empty string, so the page will not get redirected which will result in the contents of the window remaining unchanged.

Note : You cannot get the handle if the page is not on the same host as its opener