master mohon bantuannya dong. saya punya tabel id dan reg_member. keduanya nya punya field iibf_id. iibf_id di table id saya yang input, tapi iibf_id di table reg_member terisi saat user masuk di form index. nah jika ada user lain masuk dengan id yg sudah ada di reg_member maka go to index.php, jika iibf_id di reg_member msh kosong maka go to form.php

<?php 
session_start();
include('header.php');

$iibf_id = $_POST['iibf_id'];
   
//query untuk mendaptkan record dari id

$cekuser = mysql_query("SELECT * FROM id WHERE iibf_id = '$iibf_id'");
$cekid = mysql_query("SELECT * FROM reg_member WHERE iibf_id = '$iibf_id'");

//$cekuser = mysql_query("SELECT  * from  id inner join reg_member on reg_member.iibf_id=id.iibf_id");



//cek kesesuaian id

if(mysql_num_rows ($cekuser) > 0 and ($cekid) != 0 ){

    session_start();
	 $_SESSION['id']=$_POST['iibf_id'];
     ?>
   <script language="JavaScript">
	alert('silakan aktivasi !');
	document.location='form.php';
	</script>
   
   	<?php
	}
	
	 elseif(mysql_num_rows ($cekuser) > 0 and ($cekid) < 0  )  {
    
     ?>
   <script language="JavaScript">
	alert('sudah aktivasi !');
	document.location='index.php';
	</script>
   
   	<?php
       }
	   
	  else {
         echo "<div align='center'>ID Anda Tidak Terdaftar!</div>";
       }

   

?>





<script type="text/javascript">

String.prototype.trim = function() {a = this.replace(/^\s+/,'');return a.replace(/\s+$/, '');};

var emailvalreg_member = /^.+\@(\[?)[a-zA-Z0-9\-\_\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?)$/;

function cekAngka(obj){
	var x = obj.value;
	var list = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
	var status = true;	 
	for (i=0; i<=x.length-1; i++){
		// jika karakter ke-i termasuk dalam array, maka nilainya TRUE jika treg_memberak, nilai FALSE
		if (x[i] in list) cek = true; else cek = false;		
		status = status && cek;
	}
	return !status;
}

function cekJumlah(obj){
	var x = obj.value;
	var list = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
	var status = true;	 
	for (i=0; i<=x.length-1; i++){
		// jika karakter ke-i termasuk dalam array, maka nilainya TRUE jika treg_memberak, nilai FALSE
		if (x > 0) cek = true; else cek = false;		
		status = status && cek;
	}
	return !status;
}

function cekJumlah2(obj){
	var x = obj.value;
	var list = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
	var status = true;	 
	for (i=0; i<=x.length-1; i++){
		// jika karakter ke-i termasuk dalam array, maka nilainya TRUE jika treg_memberak, nilai FALSE
		if (x[i] in list) cek = true; else cek = false;		
		status = status && cek;
	}
	return !status;
}

function valreg_memberasi (){
     var vfn = document.frm_reg.fn;
	 var viibf_reg_member = document.frm_reg.iibf_reg_member;
	 var fnama = document.frm_reg.nama;
    
//     var viibf_reg_member = document.frm_reg.iibf_reg_member; 
//     var vno_reg_memberentitas = document.frm_reg.no_reg_memberentitas; 		 

	 //pengecekan
	 if(vfn.value.trim().length == 0){
	         alert("Nama harus diisi ");
	         vfn.focus();
	         return false;
	 }
	 else if(viibf_reg_member.value.trim().length == 0){
	         alert("iibf_reg_member harus diisi ");
	         viibfreg_member.focus();
	         return false;
			 
			 
	 }


//	 else if(viibfreg_member.value.trim().length == 0){
//	         alert("IIBF reg_member harus diisi ");
//	         viibfreg_member.focus();
//	         return false;
//	 }
//	 else if(cekAngka(viibf_reg_member)){
//	         alert("IIBF reg_member harus diisi dengan Angka");
//	         viibf_id.focus();
//	         return false;
//	 }
//	 else if(vno_identitas.value.trim().length == 0){
//	         alert("No. Identitas harus diisi ");
//	         vno_identitas.focus();
//	         return false;
//	 }
//	 else if(cekAngka(vno_identitas)){
//	         alert("No. Identitas harus diisi dengan Angka");
//	         vno_identitas.focus();
//	         return false;
//	 }
//	 else if(vjumlah.value.trim().length == 0){
//	         alert("Jumlah orang harus diisi ");
//	         vfn.focus();
//	         return false;
//	 }
//	 else if(cekJumlah2(vjumlah)){
//	         alert("Jumlah orang harus diisi dengan Angka");
//	         vjumlah.focus();
//	         return false;
//	 }
//	 else if(cekJumlah(vjumlah)){
//	         alert("Jumlah orang tidak boleh 0");
//	         vjumlah.focus();
//	         return false;
//	 }
	 else{
	         return true;
	 }
 }
 </script>


<body>
<div class="navbar navbar-fixed-top navbar-inverse">
    </div>
    </div>
<br/>

<div class="container" style="margin-top: 5px;">

 <div class="navbar">
    <div class="navbar-inner">
    <span class="brand"><strong><i class="icon-group icon-large"></i>&nbsp;&nbsp;FORM PENGECEKAN ID IIBF</strong></span>
    </div>

    </div>
  
<div class="thumbnail">
     <div class="row">

    <div class="span8">
	<br/>
	
	<div class="alert alert-info"><strong><i class="icon-file"></i>&nbsp;Silahkan Input ID IIBF Anda</strong></div>
	<br/>
	 <form class="form-vertical" name="frm_reg" method="POST" onSubmit="return validasi() ;" enctype="multipart/form-data">
	 
   <div class="control-group">

	<div style="margin-bottom:12px;"></div>
    </div>

    
    
   
  
<form action="login.php" method="post">
 
 
     <div class="control-group">
    <label class="control-label" for="inputEmail">ID IIBF</label>
    <div class="controls">
    <input type="text" class="span9" name="iibf_id" id="inputEmail" placeholder="iibf_id" >
	
    </div>
    </div>
  
   

    <button type="submit" name="submit" class="btn btn-success" style="margin-center:40px;"><i class="icon-save icon-large"></i>&nbsp;Submit</button>
    
    </form>