Código PHP:
/********************** Titulos ************************/
echo "<select name='a' id='a' size='6' multiple>";
if($rdo=mysql_query("select * from carreras order by carr_nom") or die("Error en carreras <br>MySQL dice: ".mysql_error()));
while($fila=mysql_fetch_array($rdo))
{
echo "<option value=".$fila['carr_id'].">".$fila['carr_nom']."</option>";
}
echo "</select>";
echo"<img src='imagen/botones/fondodeA+.jpg' alt='agregar' onClick=\"pasar_valores('a','b');copiarSelect('b');\"/>";
echo"<img src='imagen/botones/fondodeA-.jpg' alt='sacar' onClick=\"eliminar_valores('b');copiarSelect('b');\"/>";
echo "<script language='Javascript'>document.write(document.getElementById('a').options[0].text);</script>";
echo "<select name='b' id='b' size='6' multiple>";
if(empty($subDocent))
{
if($rdo=mysql_query("select * from docentes as D left join docentes_carreras as X on D.docent_id=X.docent_id left join carreras as C on X.carr_id=C.carr_id where C.facu_id>0 and D.docent_id=$iddocent") or die("Error en Docentes carreras <br>MySQL dice: ".mysql_error()));
while($fila=mysql_fetch_array($rdo))
{
echo "<option value=".$fila['carr_id'].">".$fila['carr_nom']."</option>";
}
echo "</select>";
}
else
{
echo "</select>";
echo "<script language='Javascript'> document.write(tabla[0].options[0].text);</script>";
echo "<script language='Javascript'> document.write /* probando aaui deberia ir las funcion q muestre las opciones*/(tabla.lenght);</script>";
}
echo "<script language='Javascript'> document.write(tabla[0].options[0].text);</script>";
Código HTML:
<script language='Javascript'> var tabla= Array(); function pasar_valores(de,a) { var de = document.getElementById(de); var a = document.getElementById(a); for(var i = 0, newOptions=[]; i < de.options.length; i++ ) { if( de.options[i].selected ) { newOptions.unshift({name:de.options[i].text,value:de.options[i].value}); } } if( newOptions.length > 0 ) { for(var j = 0, insert = true; j < newOptions.length; j++, insert = true ){ for( var i = 0; i < a.options.length; i++ ) { if( a.options[i].value == newOptions[j].value ) { insert = false; break; } } if( insert == true ) { var newOption = document.createElement('option'); newOption.value = newOptions[j].value; newOption.text = newOptions[j].name; if(window.ActiveXObject){a.add(newOption); } else{ a.appendChild(newOption); } } } } } function eliminar_valores(de) { var de = document.getElementById(de); for(var i = 0, remove = []; i < de.options.length; i++ ) { if( de.options[i].selected ) { remove.unshift(de.options[i]); } } for(var i = 0; i < remove.length; i++ ) { if(window.ActiveXObject){de.remove(remove[i]);} else{de.removeChild(remove[i]);} } } function copiarSelect() { for(i=0;i<arguments.length;i++) { tabla[i]=document.getElementById(arguments[i]); } } </script>