#ask a little #help

I'm trying to #remap the vocals with their accented counterparts, with a #userscript, but I don't understand anything and I don't know how to do it....
for now i found this, but it doesn't work XD

function doc_keyUp(e) {
switch (e.keyCode) {
case 97:
//a
unsafeWindow.mon_clk(160);
break;
case 101:
//e
unsafeWindow.mon_clk(138);
break;
case 105:
//i
unsafeWindow.BuySell(141);
break;
case 111:
//o
unsafeWindow.BuySell(149);
break;
case 117:
//u
unsafeWindow.BuySell(151);
break;
default:
break;
}
}
document.addEventListener('keyup', doc_keyUp, false); #ask