ok poradziłem sobie, dzięki za info
<script type="text/javascript"> var cnt = new Array();
function kontr(bCode){
var regKr = /(\*)/;
var eLem = document.getElementById(bCode).value;
regKr.test(eLem)?document.getElementById(bCode).value = '[ ' + bCode + ' ]' : document.getElementById(bCode).value = '[ ' + bCode + ' ]*';
}
function naw(N){
var regKr = /(\*)/;
var vN = document.getElementById(N).value;
return regKr.test(vN);
}
function Paste(co){
kontr(co);
var ff = document.getElementById('tresc');
if (!cnt[co]) cnt[co] = 0;
if(document.selection){
document.formularz.tresc.focus();
document.selection.createRange().text = naw(co)?'['+co+']':'[/'+co+']';
}
else if (ff.selectionStart || ff.selectionStart == 0) {
ff.focus();
var bC = naw(co)?'['+co+']':'[/'+co+']';
ff.value = ff.value.substring(0,ff.selectionStart)+bC+ff.value.substring(ff.selectionEnd,ff.value.length);
}
cnt[co]++;
}
<input type="button" id="b" name="b" value="[ b ]" onClick="Paste('b');"> <input type="button" id="i" name="i" value="[ i ]" onClick="Paste('i');"> <input type="button" id="u" name="u" value="[ u ]" onClick="Paste('u');"> <form id="formularz" name="formularz">