Waiting for Ajax call to fill global variable

I have a global javascript variable defined and am looping through a series
of rows to see if a box is clicked.
If the delete button is clicked, I see if the row clicked can be deleted
(not in a table) through an AJAX call and hold on to the
response by accumating the returning message into the global variable, then
alerting that it (may be more than 1) cannot be deleted.
Problem is, the global variable is full on the callback but when I return
after the callAjax, it's sometimes empty.
This usually happens after the first call and is usually successful after
that.
I have temporarily fixed this problem by putting an alert('getting info') to
the screen only when the global variable is empty.
I'm guessing this gives a wait for the global variable to fill.
I have tried a pause function but that doesn't always work, the alert always
does.
Has anyone else had this problem? If so, is there a more elegant way to fix
it?

Thanks in advance,

Craig

Craig Jacobsen
Sr P/A
URL Pharma
7722 Dungan Rd
Philadelphia, Pa 19111
215.697.1719