Note: You are not really checking one character at a time. You are checking (user input length) characters at a time. Because it's relatively pointless to check for one character at a time... (say the user types 'e') -- the most common character in the English language... well... pretty much every link is still going to be in your list. There's not much point in that... plus it uses a lot of processor power. The longer their input the less checking is required. SO I set a minimum amount of characters to be checked. (currently 3). If the user hasn't typed at least (3) characters nothing is checked.

Very Important Note: I have gone to extensive lengths in much of my scripting to avoid the 200,000 calculation limit that Flash has. However, in this links list there really is no way to avoid it. After you have a certain amount of links, this filtering links list will generate a huge amount of calculations. It does already. I have not seen the problem personally on this project but I know it will happen for someone out there. There are a few things you can do to solve this problem. One of them is raising the minimum input requirement before the list starts searching. The higher you set it, the fewer calculations this script will produce. Even raising it from 3 to 4 will significantly reduce calculations.