¿como poner un aviso antes de ejecucion?

[herzbazi]

proba con esto

<?php
include("../conexion.php");


$codigo_tec=$_GET['codigo_tec'];
$nombre_tec=$_GET["nombre_tec"];
$cif_tec=$_GET['cif_tec'];
$direccion_tec=$_GET['direccion_tec'];
$cp_tec=$_GET['cp_tec'];
$poblacion_tec=$_GET['poblacion_tec'];
$provincia_tec=$_GET['provincia_tec'];
$telefono_tec=$_GET['telefono_tec'];
$email_tec=$_GET['email_tec'];
$importe=$_GET['importe'];
$mano_obra_tec=$_GET['mano_obra_tec'];
$materiales_tec=$_GET['materiales_tec'];
$aviso=$_GET['aviso'];
$observaciones_tec=$_GET['observaciones_tec'];



?>
<!--java script para lanzar mensaje al eliminar-->
<script>
function eliminar(url){
if(confirm("realmente desea eliminar este registro?")){
document.location=url;
}
}
</script>
<!--java script para lanzar mensaje al eliminar-->

<form action="tecnico.php" method="get">

<table width="600" border="0" align="center">
<tr>
<td height="43" colspan="11" align="center"><font color="WHITE"><font size="5">Actualizar ficha del Tecnico</font></td>
</tr>

<tr>
<td><font color="WHITE"><b>Codigo Tecnico</b></font></td>
<?php




?>
<td style="border-width:1px"><input type="text" name="codigo_tec" value="<?=$codigo_tec?>" disabled="disabled" style="width:70%" /><input type="text" hidden="" name="codigo_tec" value="<?=$codigo_tec?>" style="width:70%" /></td>

<td colspan="4" style="border-width:1px" align="left" ><font color="WHITE"></font></td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td width="72">&nbsp;</td>
<td width="82">&nbsp;</td>
<td width="82">&nbsp;</td>
<td width="82">&nbsp;</td>
<td width="82">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td><font color="WHITE"><b>Nombre</b></font></td>
<td colspan="3" style="border-width:1px"><input type="text" name="nombre_tec" value="<?=$nombre_tec?>" style="width:100%" /></td>
<td>&nbsp;</td>
<td align="right"><font color="WHITE"><b>CIF</b></font></td>
<td colspan="6" style="border-width:1px"><input type="text" name="cif_tec" value="<?=$cif_tec?>" style="width:100%" /></td>

</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td><font color="WHITE"><b>Dirección</b></font></td>
<td colspan="10"><input type="text" name="direccion_tec" value="<?=$direccion_tec?>" style="width:100%" /></td>

</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td><font color="WHITE"><b>C.P.</font></td>
<td colspan="1"><input type="text" name="cp_tec" value="<?=$cp_tec?>" /></td>
<td align="center"><font color="WHITE"><b>Población</b></font></td>
<td colspan="2"><input type="text" name="poblacion_tec" value="<?=$poblacion_tec?>" /></td>
<td align="center"><font color="WHITE"><b>Provincia</b></font></td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td colspan="1"><input type="text" name="provincia_tec" value="<?=$provincia_tec?>" /></td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td><font color="WHITE"><b>Teléfono</b></font></td>
<td colspan="2"><input type="text" name="telefono_tec" value="<?=$telefono_tec?>" style="width:100%" /></td>
<td align="right"><font color="WHITE"><b>Email</b></font></td>
<td colspan="6"><input type="text" name="email_tec" value="<?=$email_tec?>" style="width:100%" /></td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td><font color="WHITE"><b>importe</b></font></td>
<td colspan="1"><input type="text" name="importe" value="<?=$importe?>" style="width:100%" /></td>
<td><font color="WHITE"><b>Mano obra</b></font></td>
<td colspan="1"><input type="text" name="mano_obra_tec" value="<?=$mano_obra_tec?>" style="width:100%" /></td>
<td><font color="WHITE"><b>Materiales</b></font></td>
<td colspan="1"><input type="text" name="materiales_tec" value="<?=$materiales_tec?>" style="width:100%" /></td>
<td colspan="3">&nbsp;</td>
<td colspan="2"><input type="text" name="aviso" value="<?=$aviso?>" style="width:75%" value="aviso" /></td>

</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>


<tr>
<td valign="top"><font color="WHITE"><b>Observacines</b></font></td>
<td colspan="10"><textarea name="observaciones_tec" rows="7" cols="3" style="width:100%"><?php print($observaciones_tec); ?></textarea>
</td>

</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td width="88">&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td align="center"><input type="submit" value="Actualizar datos del tecnico" name="actualizar"/></td>
<td>&nbsp;</td>
<td align="center">
<a href="nombre_de_tu_archivo.php?codigo_tec=<?php echo $codigo_tec;?>">Borrar dato del técnico</a>
</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp; </td>
<td width="88">&nbsp;</td>
</tr>
</table>

<?php
if(isset($_GET['actualizar']))

{

$link=mysqli_connect('localhost','root','','rtp') or die(mysqli_error());

$insert1="UPDATE tecnicos SET nombre_tec='$nombre_tec',cif_tec='$cif_tec',direcc ion_tec='$direccion_tec',cp_tec='$cp_tec',poblacio n_tec='$poblacion_tec',provincia_tec='$provincia_t ec',telefono_tec='$telefono_tec', email_tec='$email_tec',observaciones_tec='$observa ciones_tec',aviso='$aviso', mano_obra_tec='$mano_obra_tec',importe='$importe', materiales_tec='$materiales_tec' where codigo_tec='$codigo_tec'";

$result=mysqli_query($link,$insert1);

if ($result==1)
{
?><p align="center" style="font-size:18px"><font color="yellow"><?php echo"el Tecnico $nombre_tec se a actualizado con exito";?></font></p>
<?php
}
else
{
?>
<p align="center" style="font-size:18px"><font color="red"><?php echo "El Tecnico $nombre_tec no se a actualizado. Revisa que has introducido todos los datos";?></font></p>
<?php
}

}

if(isset($_GET['borrar']))

{
?>

<?php

$link=mysqli_connect('localhost','root','','rtp') or die(mysqli_error());

$insert3="DELETE FROM tecnicos WHERE codigo_tec='$codigo_tec'";

$result3=mysqli_query($link,$insert3);

if ($result3==1)
{
?><p align="center" style="font-size:18px"><font color="yellow"><?php echo"La ficha del Tecnico $nombre_tec se a borrado con exito";?> </font></p>
<?php

}
else
{
?>
<p align="center" style="font-size:18px"><font color="red"><?php echo "la ficha del Tecnico $nombre_tec no se a borrado.";?></font></p>
<?php
}

}

?>