returning value on php function and pass javascript parameter

[filipelou]

<a href="novidades.php?id=" onclick=" if(XXXX) this.href+=document.getElementById('dominio').value;else alert('SubDominio não encontrado!!')">Ver Novidades</a>

 

where is xxxxx i want this function on external php

 

function mostra_idDominio($nomeDominio){

 

 

 

ligarDB();

 

 

$query="select id from subdominios where nomeSub='$nomeDominio'";

$resultado=mysql_query($query);

    $row = mysql_fetch_assoc($resultado);

$num=mysql_numrows($resultado);

   

if ($num>0){

        return ($row['id']);

}

else{

 

  return -1;

 

  }

 

desligarDB();

 

}

 

to that i have to pass document.getElementbyId('Dominio').value and check if it is !=-1.

 

How to do that?

[mainewoods]

the ways to get a value from javascript to php are:

1) submit a form - reloads page

2) call a link with url passed parameters - reloads page

3) use ajax - does not reload page but requires the most coding