odeslání na input podle proměnné

<form name="pridat">
<input type="radio" onClick="hexacislo()" name="_bit1_" >ano
<input type="radio" onClick="hexacislo()" name="_bit1_" checked="checked">ne
<input type="radio" onClick="hexacislo()" name="_bit2_" >ano
<input type="radio" onClick="hexacislo()" name="_bit2_" checked="checked">ne
<script language="JavaScript" type="text/javascript">
    
    var bit1,bit2,permission;
    function hexacislo()
    {
        if (document.pridat._bit1_[0].checked){bit1=1;}
        else{bit1=0;}
        if (document.pridat._bit2_[0].checked){bit2=1;}
        else{bit2=0;}
        x=bit1*1+bit2*2;
        return x;
    }
    permission=hexacislo(permission);
    document.write(permission);
    document.getElementById("_permission_").value ='permission';
</script>
<input type="text" size="18" id="_permission_" name="_permission_">
</form>

<form name="pridat">
<table>
<tr><td><input type="radio" onchange="hexacislo()" name="_bit1_" >ano<input type="radio" onchange="hexacislo()" name="_bit1_" checked="checked">ne</tr></td>
<tr><td><input type="radio" onchange="hexacislo()" name="_bit2_" >ano<input type="radio" onchange="hexacislo()" name="_bit2_" checked="checked">ne</tr></td>
</table>
<script language="JavaScript" type="text/javascript">
var bit1,bit2,permission;
var formular = document.pridat; 
function hexacislo()
{
		if (formular._bit1_[0].checked){bit1=1;}
		else{bit1=0;}
		if (formular._bit2_[0].checked){bit2=1;}
		else{bit2=0;}  
		permission=bit1*(Math.pow(2,0))+bit2*(Math.pow(2,1));
		formular['data'].value = permission;    
}
</script>
<table>
<tr><td><input type="text" size="18" id="data"  name="_permission_" value="0"></tr></td>