a/<form ... name="all_submit"> //Pour valider la totalité du formulaire
          mon checkbox qui coche tout

        Ma boucle while
            b/<form ... name="1erform"> //pour valider une modification
                pleins de truc + MES FAMEUX CHECKBOX
                 avec bouton onclick submit 1erform         
             b/</form>

             c/<form ... name="2emeform"> //pour editer mon contenu
                avec bouton onclick submit 2emeform         
             c/</form>

              d/<form ... name="3emeform"> //pour supprimer mon contenu
                 avec bouton onclick submit 3emeform         
              d/</form>
        FIN de ma boucle while

avec bouton onclick submit all_submit
a/</form>

Les formulaires imbriqués c'est pas bon...

<script type="text/javascript">
/* <![CDATA[ */
var checkflag = "false";
function check(field)
{
    if (checkflag == "false")
    {
        for (i = 0; i < field.length; i++)
        {
            field[i].checked = true;
        }
        checkflag = "true";
        return "Tout décocher";
    }
    else
    {
        for (i = 0; i < field.length; i++)
        {
            field[i].checked = false;
        }
        checkflag = "false";
        return "Tout cocher";
    }
}
/* ]]> */
</script>

<input type="checkbox" value="Cocher" onClick="this.value=check(this.form.elements['suppbox[]'])"> 

<input type="checkbox" value="Cocher" onClick="this.value=check(this.form.elements['suppbox']);"> 

<form action="essai" method="post" name="all_submit">
<table width="100%" border="0" cellspacing="2" cellpadding="0">
  <tr>
  	<td width="1" class="couleurs1">
    <img src="../images_site/petites_icones/supprimer.png" alt="Tout supprimer" title="Tout supprimer"/>
    </td>
    <td width="1" class="couleurs1">ID&nbsp;</td>
    <td class="couleurs1">Titre</td>
    <td class="couleurs1">Date</td>
    <td width="1" class="couleurs1">Online&nbsp;</td>
    <td width="1" class="couleurs1">Posteur&nbsp;</td>
    <td colspan="3" class="couleurs1">Gestion</td>
    </tr>
    <tr>
    <td width="1" class="couleurs1">
    <input type="checkbox" value="Cocher" onClick="this.value=check(this.form.elements['suppbox[]'])"></td>
    <td width="1" class="couleurs1">&nbsp;</td>
    <td class="couleurs1">&nbsp;</td>
    <td class="couleurs1">&nbsp;</td>
    <td class="couleurs1">
      <div align="center">
      <?php
	echo alldesactive($online_offline, $chp_page, "Tout Offline", "Tout Online");
	  ?>
      </div></td>
    <td class="couleurs1">&nbsp;</td>
    <td colspan="3" class="couleurs1">&nbsp;</td>
    </tr>
    
<?php

	while($row_txtacc= mysql_fetch_assoc($sql_acctt))
	{
		if ($row_txtacc['txtallaccueil_id'] == $editer_accueil)
		{
		$class = "couleurs3";
		$couleurs = $couleurs;
		}
		elseif ($couleurs == "0")
		{
		$class = "couleurs1";
		$couleurs = "1";
		}
		else
		{
		$class = "couleurs2";
		$couleurs = "0";
		}
	///Parametres	
	$online_offline.= $row_txtacc['txtallaccueil_online'];
	?>  
      
	  <tr>
      <form action="index.php?page=0" method="post" name="valider">
      
      <td class="<?php echo $class; ?>">
      <input name="suppbox[]" type="checkbox" id="suppbox[]" value="1" />
            </td>
		<td class="<?php echo $class; ?>">
        <div align="center"><?php echo $row_txtacc['txtallaccueil_id']; ?></div>        </td>
		<td class="<?php echo $class; ?>">
        <input name="txtallaccueil_titre" type="text" value="<?php echo stripslashes($row_txtacc['txtallaccueil_titre']); ?>" size="35" />        </td>
		<td class="<?php echo $class; ?>"><?php echo date('d/m/Y H:m:s',$row_txtacc['txtallaccueil_date']); ?></td>
		<td class="<?php echo $class; ?>"><div align="center"><?php echo online($row_txtacc['txtallaccueil_online']); ?></div></td>
		
		<td class="<?php echo $class; ?>"><div align="center"><?php echo posteur($row_txtacc['txtallaccueil_user_id']); ?></div></td>
		<td width="1" class="<?php echo $class; ?>">
		
		<input name="txtallaccueil_id" type="hidden" value="<?php echo $row_txtacc['txtallaccueil_id']; ?>" />
		<input name="valider" type="hidden" value="accueil" />
        <?php echo $chp_page; ?>
        <input name="userid" type="hidden" value="<?php echo $_SESSION['cb_user']->userid; ?>" />
		<input name="valider" type="button" value="Valider" onclick="submit('valider')"/>        </td>
        </form>
		
		<td width="1" class="<?php echo $class; ?>">
		<form action="index.php?page=<?php echo $_GET['page']; ?>" method="post" name="editer">
		<input name="editer_accueil" type="hidden" value="<?php echo $row_txtacc['txtallaccueil_id']; ?>" />
		<input name="valider" type="hidden" value="accueil" />
        <?php echo $chp_page; ?>
		<input name="editer" type="button" value="Editer" onclick="submit('editer')"/>
		</form>        </td>
		
		<td width="1" class="<?php echo $class; ?>">
        <form action="index.php?page=<?php echo $_GET['page']; ?>" method="post" name="supprimer">
		<input name="supprimer_accueil" type="hidden" value="<?php echo $row_txtacc['txtallaccueil_id']; ?>"/>
		<input name="valider" type="hidden" value="accueil" />
        <?php echo $chp_page; ?>
		<input name="supprimer" type="button" value="Supprimer" class="bt_supprimer" onclick="submit('supprimer')"/>
		 </form>        </td>
         
	  </tr>
        
	 <?php
	}
?> 
</table>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td class="couleurs1">
    <input name="tt_supprimer" type="button" value="Tout supprimer" class="bt_supprimer" onclick="submit('all_submit')"/>
</td>
  </tr>
</table>

</form>

<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
var checkflag = "false";
function check(field) {
if (checkflag == "false") {
  for (i = 0; i < field.length; i++) {
  field[i].checked = true;}
  checkflag = "true";
  return "Tout décocher"; }
else {
  for (i = 0; i < field.length; i++) {
  field[i].checked = false; }
  checkflag = "false";
  return "Tout cocher"; }
}
//  End -->
</script>

<input type="checkbox" value="Cocher" onClick="this.value=check(this.form.elements['suppbox[]'])">

<input name="suppbox[]" type="checkbox" id="suppbox[]" value="1" />