Js php multiple selection delete

if("确认删除"){

$num=$_POST['checkbox'];

foreach($num as $v){

        $sql="delete from aa where id =".$v;
        $aa=mysql_query($sql);
        echo "";
    }
}
?>


<script></li>
<li>var checkflag = "false";</li>
<li>function check(fieldName) {</li>
<li>    var field=document.getElementsByName(fieldName);</li>
<li>    if (checkflag == "false") {</li>
<li>        for (i = 0; i < field.length; i++) {</li>
<li>        field[i].checked = true;</li>
<li>    }</li>
<li>    checkflag = "true";</li>
<li>    return "全选";</li>
<li> </li>
<li>}else {</li>
<li>    for (i = 0; i < field.length; i++) {</li>
<li>        field[i].checked = false; }</li>
<li>        checkflag = "false";</li>
<li>        return "全选"; </li>
<li>    }</li>
<li>}</li>
<li></script>