bang mau nanya nih,, napa hanya bisa menginput semester awal saja..ketika input semester pertengahan gak berhasil menginput kodekuliah..
ini sorce'y
modkrs.php
<html>
<head>
</head>
<body>
<? 
include "config/koneksi.php";
$start_time = strtotime("2010-01-27");
$end_time = strtotime("2019-09-26");
$current_time = time();
if($current_time < $start_time || $current_time > $end_time){
 echo "Maaf, waktu untuk pengisian atau pengeditan KRS sudah berakhir";
 echo " <p><input type='button' value='kembali' onclick=self.history.back()>";
session_start();
include "config/koneksi.php";
}else{
$was = mysql_query("SELECT * FROM mhs WHERE KDPRODI = '$_SESSION[NIMHS]'");
while($pada = mysql_fetch_array($was)){
$PRODI_MHS=$_SESSION['KDPRODI'];
}
$bln_sekarang=date("m");
$operator = '!=';
if($bln_sekarang < 6){ //genap
$operator = '=';
}
$sql =mysql_query ("select * from jadwal1 inner join makul on makul.KDMKM=jadwal1.KDMKM where jadwal1.SEMESTER % 2 $operator 0 and makul.KDPRODI = '$PRODI_MHS' order by jadwal1.SEMESTER asc");
while($k=mysql_fetch_array($sql)){
$kode[]=$k['KDMKM'];
$nama[]=$k['NAKMK'];
$hari[]=$k['HARI'];
$jam[]=$k['JAM'];
$sks[] = $k['SKSMK'];
$semester[]=$k['SEMESTER'];
$ruang[]=$k['KDRUANG'];	
$kelas[]=$k['kdkelas'];
$nmbu[]=$k['BU'];
$kdwp[]=$k['KDWP'];
}
?>
<html>
<head>
<title>Check Box KRS</title>
<script>
<?php
echo "var jumlah = ".count($kode).";\n";
echo "var sks = new Array();\n";
//mengambil sks matakuliah dan memasukkan ke array javascript
for($j=0;$j<count($kode);$j++){
    echo "sks['".$kode[$j]."'] = ".$sks[$j].";\n";
}
?>
function hitungtotal(){
    jum = 0;
    for(i=0;i<jumlah;i++){
        id = "mk"+i;
        td1 = "k1"+i;
        td2 = "k2"+i;
        td3 = "k3"+i;
        td4 = "k4"+i;
		td5 = "k5"+i;
		td6 = "k6"+i;
		td7 = "k7"+i;
		 td8 = "k8"+i;td9 = "k9"+i;
        if(document.getElementById(id).checked){
            kode = document.getElementById(id).value
            jum = jum + sks[kode];
            //untuk mengubah warna latar tabel apabila diceklist
            document.getElementById(td1).style.backgroundColor = "#";
            document.getElementById(td2).style.backgroundColor = "#";
            document.getElementById(td3).style.backgroundColor = "#";
            document.getElementById(td4).style.backgroundColor = "#";
	 document.getElementById(td5).style.backgroundColor = "#";
	  document.getElementById(td6).style.backgroundColor = "#";
	   document.getElementById(td7).style.backgroundColor = "#";
	    document.getElementById(td8).style.backgroundColor = "#";
		document.getElementById(td9).style.backgroundColor = "#";
        }else {
            document.getElementById(td1).style.backgroundColor = "white";
            document.getElementById(td2).style.backgroundColor = "white";
            document.getElementById(td3).style.backgroundColor = "white";
            document.getElementById(td4).style.backgroundColor = "white";
 document.getElementById(td5).style.backgroundColor = "white";
  document.getElementById(td6).style.backgroundColor = "white";
   document.getElementById(td7).style.backgroundColor = "white";
    document.getElementById(td8).style.backgroundColor = "white";
	document.getElementById(td9).style.backgroundColor = "white";
        }
    }
    //menampilkan total jumlah SKS yang diambil
    document.getElementById("jsks").innerHTML = jum;
}
</script>
</head>
<body>
<?php
$query="SELECT	* from mhs inner join prodi on mhs.KDPRODI=prodi.KDPRODI where NIMHS='".$_SESSION['NIMHS']."'";
		  $result=mysql_query($query);
		  $data=mysql_fetch_array($result);
		
		
		$bln_sekarang=date("m");
				if($bln_sekarang >05 and $bln_sekarang<=12){
			$thn_sekarang .="2";
			$sem="Gasal";
		}else{
			$thn_sekarang .="1";
			$sem="Genap";
		}
echo"<table width=\"500\" cellspacing=5 border=\"0\"><tr><td rowspan=\"5\" valign=\"top\" align=\"justify\">
<tr>
				<td>Nama</td><td>: $data[NMMHS]</td>";
				echo "<td>NIM</td><td>: $data[NIMHS]</td></tr>";
				$tahun=date("Y");
				$th1=$tahun+1;
				echo"<tr><td>Semester</td><td>: $data[KDSEMES]/ $sem </td>
					<td>Tahun akademik</td><td>: $tahun/$th1</td></tr>
				<tr><td>Program Studi</td><td>: $data[PRODI]</td>
			";
$dosen=mysql_query("select * from mhs inner join dosen on mhs.NIDN=dosen.NIDN  where NIMHS='$_SESSION[NIMHS]'");
	
	while ($dos=mysql_fetch_array($dosen)){
	$dosennya=$dos['NMDOS'];
	echo "<td>Dosen Wali</td><td> : $dosennya </td></tr>";
	}
	$ip = mysql_query("select * from nilai WHERE NIMHS = '$_SESSION[NIMHS]'");
   
   while($l = mysql_fetch_array($ip)){
     $ipnya = $l['IPS'];
	 if($ipnya>=3){
														$sks_dptdiambil="24 sks";
													}
													elseif($ipnya>=2.5 and $ipnya<3){
														$sks_dptdiambil="21 sks";
													}
													elseif($ipnya>=2 and $ipnya<2.5){
														$sks_dptdiambil="18 sks";
													}
													elseif($ipnya>=1.5 and $ipnya<2){
														$sks_dptdiambil="15 sks";
													}
													else{
														$sks_dptdiambil="12 sks";
													}
     echo "<tr>";
     echo "<td >Ip Sebelumnya</td><td>:  $ipnya</td>";
     echo "<td >Jumlah SKS Y.A.D</td><td>: $sks_dptdiambil";
    
   echo "</td></tr></table>";
  }
  ?>
<p><form name="formkrs" method="POST" action="index1.php?hal=inputkrs">
<table border=1 width="96%" style="border-collapse:collapse" bordercolor="#999999">
<tr><td bgcolor="#999999" ><b>Kode</b></td>
<td bgcolor="#999999" ><b>Nama Mata Kuliah</b></td>
<td bgcolor="#999999" ><b>W/P</b></td>
<td bgcolor="#999999"  align="center"><b>SKS</b></td>
<td bgcolor="#999999" ><b>HARI</b></td>
<td bgcolor="#999999"  align="center"><b>JAM</b></td>
<td bgcolor="#999999"  align="center"><b>KELAS</b></td>
<td bgcolor="#999999"  align="center"><b>RUANG</b></td>
<td bgcolor="#999999"  align="center"><b>SEMESTER</b></td>
<td bgcolor="#999999"  align="center"><b>B/U</b></td>
<td bgcolor="#999999"  align="center"><b>Ambil</b></td></tr>
<?php
//menampilkan matakuliah ke dalam tabel
		
        
for($i=0;$i<count($kode);$i++){
    echo '<tr bgcolor="white"><td id="k1'.$i.'">'.$kode[$i].'</td>';
    echo '<td  id="k2'.$i.'">'.$nama[$i].'</td>';   
	echo '<td align="center"  id="k2'.$i.'">'.$kdwp[$i].'</td>'; 
	echo '<td align="center" id="k3'.$i.'">'.$sks[$i].'</td>';
	echo '<td id="k4'.$i.'" align="center">'.$hari[$i].'</td>';
	echo '<td align="center" id="k5'.$i.'">'.$jam[$i].'</td>';  
	//echo '<td align="center" id="k6'.$i.'">'.$nidn[$i].'</td>';
	echo '<td align="center" id="k6'.$i.'">'.$kelas[$i].'</td>';
	echo '<td align="center" id="k7'.$i.'">'.$ruang[$i].'</td>';
	echo '<td align="center" id="k8'.$i.'">'.$semester[$i].'</td>'; ?>
<td>
 <select name="nmbu[]" >
 	<option value=""> -- </option>
       
     
	  <? $pt = mysql_query("SELECT * FROM mkbu");		
			while($rpt=mysql_fetch_array($pt)){
          	  echo "<option value=\"$rpt[BU]\">$rpt[BU]</option>";
            }	
		?>
      </select> </td>
	<? //echo "<td align='center' id=k3$i>".$prodi[$i]."</td>";
		//<td id="k4'.$i.'"><input type="checkbox" name="mk[]" onclick="hitungtotal()" value="'.$kode[$i].'" id="mk'.$i.'"/></td>
    echo '<td align="center" id="k9'.$i.'"><input type="checkbox" name="mk[]" 
	onclick="hitungtotal()" value="'.$kode[$i].'" id="mk'.$i.'"/></tr>';
}
?>
<tr><td colspan=9	>JUMLAH YANG DIAMBIL</td><td align="center">
<span id=jsks></span></td></tr>
</table>
<br/>
<input name="kirim" type="submit"  value="Kirim KRS">  
<? } ?></form>
</body> 
</html>
dan ini proses'y
inputkrs.php
<?php
session_start();
include "config/koneksi.php";
$tahun= date("Y");
$NIMHS==$_SESSION['NIMHS'];
$was = mysql_query("SELECT * FROM mhs WHERE NIMHS = '$_SESSION[NIMHS]'");
$pada = mysql_fetch_array($was);
$semester = $pada['KDSEMES'];
$NMMHS = $pada['NMMHS'];
$mk = mysql_query("SELECT * FROM krs1 WHERE NIMHS = '$_SESSION[NIMHS]'");
$cek = mysql_query("SELECT * FROM krs1 WHERE NIMHS='$NIMHS' and KDSEMES='$semester' and tahun='$tahun'  ");
if(mysql_num_rows($cek) > 0  ){
    die("<br/>Anda sudah melakukan pengisian KRS pada semester ini !! <br>
	Jika ingin mengisi ulang KRS semester ini, hapus dahulu KRS semester ini !! <br><br/>
	<input type='button' value='kembali' onclick=self.history.back()>");	 
}
if((!empty($_POST['nmbu'])) and (!empty($_POST['mk']))){	
		$nmbu_ = $_POST['nmbu'];
		$hitnmbu = count($nmbu);
		$mk_ = $_POST['mk'];
		$hitmk = count($mk_);
		
	}
	if((empty($_POST['nmbu'])) and (empty($_POST['mk']))){
		echo "<script>alert('Maaf, mohon lengkapi input yang tersedia !');history.go(-1);</script>";
	}else{
		$lolos = true;
	}
	if($lolos){
		for($x=0;$x<$hitnmbu;$x++){
			if(!empty($nmbu_[$x])){
			   mysql_query("insert into krs1 (NIMHS,NMMHS,kodekuliah,SKSMK,BU,KDSEMES,tahun) values ('$NIMHS','$NMMHS','$mk_[$x]','$sks','$nmbu_[$x]','$semester','$tahun')");
			  }
		}
	}
echo"NIM : $NIMHS<br>";
echo"Semester : $semester<br>";
echo"Tahun : $tahun<br>";
?>
Berikut KRS yang anda ambil :
		<table border=1 width=400 style="border-collapse:collapse" bordercolor="#999999">
		<tr><td><b>No</b></td>
		<td><b>Kode</b></td>
		<td><b>Nama Mata Kuliah</b></td>
		<td><b>MK B/U</b></td>
		<td><b>SKS</b></td>
		
		<?
		$tampilkrs=mysql_query("SELECT * FROM krs1, makul where NIMHS = '$_SESSION[NIMHS]'  AND krs1.kodekuliah = makul.KDMKM	and krs1.KDSEMES='$semester' and krs1.tahun='$tahun'");
		$jum = 0;
		$i = 1;
		$jummk = 0;
		while ($k=mysql_fetch_array($tampilkrs)){
			echo "<tr><td>$i</td>";
			echo "<td>".$k['KDMKM']."</td>";
			echo "<td>".$k['NAKMK']."</td>";
			echo "<td align='center'>".$k['BU']."</td>";
			echo "<td align='center'>".$k['SKSMK']."</td>";
			$jummk = $jummk + $k['KDMKM'];
			$jum = $jum + $k['SKSMK'];
			$i++;
}
echo "<tr><td></td><td></td><td colspan=2>Jumlah KRS yang diambil</td><td align='center'>$jum</td></tr>";
			 mysql_query("insert into jumlah(NIMHS,JUMSKS,KDSEMES,tahun) values ('$NIMHS','$jum','$semester','$tahun')");	
?>
</table>