<?phpsession_start();if($_POST){ $_SESSION[‘old‘]=array(‘one‘,‘two‘,‘three‘,‘four‘,‘five‘); $_SESSION[‘old‘]=array(); $_SESSION[‘old‘]=array(‘two‘,‘five‘); $new=(array) $_POST[‘big‘]; foreach($new as $k=>$v){ if(!in_array($v,$_SESSION[‘old‘])){ $_SESSION[‘old‘][]=$v; echo ‘add ‘.$v; echo ‘<br />‘; }else{ echo ‘mod ‘.$v; echo ‘<br />‘; } } foreach($_SESSION[‘old‘] as $k=>$v){ if(!in_array($v,$new)){ $id=array_keys($_SESSION[‘old‘],$v); unset($_SESSION[‘old‘][$id[0]]); echo ‘del ‘.$v; echo ‘<br />‘; } } echo "<pre>"; print_r($_SESSION[‘old‘]);}?><form method="post"><input type="checkbox" name="big[]" value="one" /> one<br /><input type="checkbox" name="big[]" value="two" /> two<br /><input type="checkbox" name="big[]" value="three" /> three<br /><input type="checkbox" name="big[]" value="four" /> four<br /><input type="checkbox" name="big[]" value="five" /> five<br /><input type="submit" value="submit" name=‘abc‘></form>原文：http://www.cnblogs.com/songzhenghe/p/4582320.html