<script language="JavaScript">  
var lat=new Array("jo","zh","i'","ch","sh","xh","je","ju","ja","a","b","v","g","d","e","z","i","k","l","m","n","o","p","r","s","t","u","f","x","c","'","   y","`","j","h");    
var cyr=new Array("ё","ж","й","ч","ш","щ","э","ю","я","а","б","в","г","д","е","з","и","к","л","м","н","о","п","р","с","т","у","ф","х","ц","ь","ы","ъ","ж   ","х");    

var latcap=new Array("JO","Jo","ZH","Zh","I'","Ch","CH","Sh","SH","Xh","XH","Je","JE","Ju","JU","Ja","JA","A","B","V","G","D","E","Z","I","K","L","M","N","   O","P","R","S","T","U","F","X","C","Y","J","H");    
var cyrcap=new Array("Ё","Ё","Ж","Ж","Й","Ч","Ч","Ш","Ш","Щ","Щ","Э","Э","Ю","Ю","Я","Я","А","Б","В","Г","Д","Е","З","И","К","Л","М","Н","О","П","Р","С","Т   ","У","Ф","Х","Ц","Ы","Ж","Х");    

function translate(tex)  
{  
var buf=tex;  
var i;  
for (i=0;i<latcap.length;i++)  
    {  
    buf=replace(buf,latcap[i],cyrcap[i],1,0);  
    }  

for (i=0;i<lat.length;i++)  
    {  
    buf=replace(buf,lat[i],cyr[i],1,0);  
    }  

tex=buf;  
return tex;  
}  

function replace(target,oldTerm,newTerm,caseSens,wordOnly) {  

    var work = target;  
    var ind = 0;  
    var next = 0;  

    if (!caseSens) {  
    oldTerm = oldTerm.toLowerCase();  
    work = target.toLowerCase();  
    }  

    while ((ind = work.indexOf(oldTerm,next)) >= 0) {  
    if (wordOnly) {  
    var before = ind - 1;  
    var after = ind + oldTerm.length;  
    if (!(space(work.charAt(before)) && space(work.charAt(after)))) {  
    next = ind + oldTerm.length;  
    continue;  
    }  
    }  
    target = target.substring(0,ind) + newTerm +  
    target.substring(ind+oldTerm.length,target.length);  
    work = work.substring(0,ind) + newTerm +  
    work.substring(ind+oldTerm.length,work.length);  
    next = ind + newTerm.length;  
    if (next >= work.length) { break; }  
    }  

    return target;  

}  
</script>

<input type="button" value="Транслит" onclick="document.forms['addform'].message.value=translate(document.forms['addform'].message.value);" />