Bu jqueri bi çözemedim gitti

@Seyranli

verdiğin örneği denedim ama yine b.php'ye yönleniyor

Bu a.php
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-9" />
<title>Untitled Document</title>
<script type="text/javascript" src="jquery.form.js"></script>
<script type="text/javascript">
$("form#form1").ajaxForm({
target: "#sonuc"
});
</script>
</head>
<body>
<form name="form1" id="form1" method="post" action="b.php?do=form&kac=1">
  <table width="400" border="1" align="center">
    <tr>
      <td>ad</td>
      <td>:</td>
      <td><input type="text" name="a" id="a"></td>
    </tr>
    <tr>
      <td>soyad</td>
      <td>:</td>
      <td><input type="text" name="b" id="b"></td>
    </tr>
    <tr>
      <td>yedekad</td>
      <td>:</td>
      <td><input type="text" name="c" id="c"></td>
    </tr>
    <tr>
      <td>yaş</td>
      <td>:</td>
      <td><input type="text" name="d" id="d"></td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td>&nbsp;</td>
      <td><input type="submit" name="button" id="button" value="Yolla"></td>
    </tr>
  </table>
</form>


<div id="sonuc"></div>
</body>
</html>
Buda b.php
if($_GET['do']=="form"):
    if($_GET['kac']==1):
    $a = $_POST["a"];
    $b = $_POST["b"];
    $c = $_POST["c"];
    $d = $_POST["d"];
    
        if(empty($a) || empty($b) || empty($c) || empty($d)):
            echo "alanlar boş";
        elseif($a != $b):
            echo 'a ve b eşit değil';
        elseif($a == $c):
            echo 'a ve c birbirine eşit';
        elseif($a != $d):
            echo 'a ve d eşit değil';
        else:
            echo 'diğer şartlar sağlandı';
        endif;
    endif;
endif;
Yardımcı olurmusunuz ?