Nuke Conversion Js

The javascript (conversion.js) which is used on decimal input fields (MifosDecimalInput.java, or mifos:mifosdecimalinput in places like feesedit.jsp), has many problems:

1. The discrepency between keypad and normal number keys (issue 554). Seems to be Firefox only. With IE, I get the same behavior with either kind of key (which is that attempting to type a second digit after the decimal point causes it to flash and go away).
2. After typing the keypad second digit, then other keys which used to work (like arrows and backspace) stop working (again, Firefox only).
3. Per discussion with Emily, it is poor user experience for a user to type things and have them not show up on the screen. Currently, this is true by design for anything but numbers, as far as I can tell. A better design is to wait until the user clicks Preview, and then show the errors on the page. (That we should wait for Preview is one of our HTML Standards .
4. The javascript lacks tests. Javascript can be tested with something called JSUnit, but we are not doing that.
5. Other Firefox features, like control-T to open a new tab, stop working when that field is active. I couldn't find an IE feature which stopped working although I'm not sure this is Firefox-specific.
6. The javascript has strange complications, like trying to handle Hindi and Arabic (as opposed to Western/international) digits. This is not a requirement now, and maybe not ever.

The desired direction is to get rid of conversion.js, and replace it with server-side validation. MifosDecimalInput is used in about 50 places, and the quick fix of ripping out the javascript is not sufficient - one gets internal errors on preview.

Some related (or possibly related) bugs in the Issue Tracker are 55, 178, and 554.