Javascript Global Regex Match

I needed to do a case insensitive, multiline, global regex (/img) over some html. The matches kept coming back wrong using $.each() and Mozilla's directions. The while loop on the Mozilla docs site didn't work for me, every time it returned match as "true." That's no help, of course. So, a do while loop instead, and all is well.

var regex = /./gim;
var matches = [];
var match;
match = regex.exec(text);
while (match instanceof Array) {
  matches.push(match);
  match = regex.exec(text);
}
var regex = /./gim;
var matches = [];
var match;
match = regex.exec(text);
while (match instanceof Array) {
  matches.push(match);
  match = regex.exec(text);
}