I wanted to post a reply here because I found this thread as a result of searching to find an answer to the same problem. This thread pointed me in the direction I finally went in and this worked (I'm writing an HTA so if it works there it should work in IE.) Also note I'm using the wonderfully inflexible VBScript to get this one to work. Javascript should be similar or even easier...

[CODE=asp]Function fncShowPass()
...