php html javascript wrong result

Question

This is my code

<html>
<head>
    <title>
        Aplikasi KRS
    </title>
</head>
<body>
<p>IPK : 1.xx</p>
    <form name="formTes" method="post">
        <script>
            function cekKrs()
            {
                var jum_sks = 0;
                for(var i=0; i<7; i++)
                {
                    if(document.formTes.elements[i].checked)
                        jum_sks += mataKuliah;
                }


                document.formTes.fieldJumlah.value = jum_sks;

                if(jum_sks > 15)
                {
                    alert("Anda harus mengurangi SKS\n karena melebihi 15 SKS");
                }

            }

            function cekKirim()
            {
                if(document.formTes.fieldJumlah.value > 15)
                    alert("Anda harus mengurangi SKS\n karena melebihi 15 SKS");
                else
                    window.location.href = "tesform.html";
            }
        </script>

        <table border="2">
        <tr><th>Kode</th><th>Mata Kuliah</th><th>SKS</th><th><Pilihan/th></tr>
        <?php 
            include "koneksi.php";
            $sql = "SELECT * FROM mata_kul";
            $query = $con->query($sql);
            while($mataKuliah = $query->fetch_array())
            {
                echo "<tr><td>". $mataKuliah['kodeMK'] ."</td>";
                echo "<td>". $mataKuliah['namaMK'] ."</td>";
                echo "<td>". $mataKuliah['sks'] ."</td>";
                echo "<script>var mataKuliah= ".$mataKuliah['sks']."</script>";
                echo "<td><input name='mk". $mataKuliah['kodeMK'] ."' type='checkbox' onclick='cekKrs()'></td>";
            }
        ?>
        <tr><td colspan="2" align="right">Jumlah SKS</td>
        <td colspan="2"><input size="3" value="0" name="fieldJumlah" type="text" readonly="readonly"></td></tr></table>
        <br>
        <input type="button" name="tombolKirim" value="Kirim" onclick="cekKirim()">
    </form>
</body>
</html>

My question is

"Why when i click checklist it show the last value of sks in jumlah SKS, not the sks checked value i click ? like when i click checklist which have value of 2 in sks it should show 2 not 8 in jumlah SKS"

Here's the image It's my php

Can you tell me where did i go wrong ? I'm still new

You have a lot of variables named 'mataKuliah' in javascript... the last one = 8 ... — Mate
– Mate, Commented Feb 11, 2015 at 3:12
I guess you need send the checkbox obj as param to cekKrs() , and in function cekKrs evaluates if obj is checked to + or - the obj.value from total — Mate
– Mate, Commented Feb 11, 2015 at 3:21
I already send the value <input name='mk". $mataKuliah['kodeMK'] ."' type='checkbox' onclick='cekKrs(mataKuliah)> then in function cekKrs(var mataKuliah) but now it's not showing any number at all :( — user2977799
– user2977799, Commented Feb 11, 2015 at 3:28
You should insert your HTML script so other can check it easily if it relate to javascript issue — Joko Wandiro
– Joko Wandiro, Commented Feb 11, 2015 at 6:04

Mate · Accepted Answer · 2015-02-11 04:03:11Z

2

I guess you need send the checkbox obj as param to cekKrs() , and in function cekKrs evaluates if obj is checked to + or - the obj.value from total

Try this DEMO

HTML ( draft )

<table>
<!-- while($mataKuliah = $query->fetch_array()) 
        { -->
    <tr>
      <!-- echo "<td><input name='mk". $mataKuliah['kodeMK'] ."' type='checkbox' onclick='cekKrs(this)' value='".$mataKuliah['sks']."'></td>";    // PHP  -->
       <td><input type='checkbox' onclick='cekKrs(this)' value='1'>1</td>
    </tr>
    <tr>
       <td><input type='checkbox' onclick='cekKrs(this)' value='2'>2</td>
    </tr>
    <tr>
       <td><input type='checkbox' onclick='cekKrs(this)' value='3'>3</td>
    </tr>
    <!-- } -->
</table>
<input size="3" value="0" name="fieldJumlah" id='fieldJumlah' type="text" readonly="readonly">

onclick='cekKrs(this)' sends checkbox obj , and you keep the mataKuliah's value inside the checkbox value

JS

 function cekKrs(chkObj)
            {
                //Get current total
                var jum_sks = parseInt(document.getElementById('fieldJumlah').value);
                //Get checkbox value clicked
                var mataKuliah = parseInt(chkObj.value);

                    //Evaluate check to + or -
                    if(!chkObj.checked)
                    {
                        mataKuliah = (mataKuliah * -1)
                    }

                    jum_sks += mataKuliah;

                 //Set new total
                 document.getElementById('fieldJumlah').value = jum_sks;


            }

edited Feb 11, 2015 at 4:03

answered Feb 11, 2015 at 3:32

Mate

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4 Comments

user2977799 Over a year ago

Yeah, it's working in the example, but, i'm using database and array, and looping while :( did not exactly specify id manually :( i try what you suggest on it, it did not show any chnge when click :( but thnx for the answer :) i have something to do, I'll see it later thnx for the answer. :)

Mate Over a year ago

Great! Check php commented code. It's the same, you only need add value='".$mataKuliah['sks']."' to your checkbox ... and change cekKrs(this)

Mate Over a year ago

You don't need any id manually or concatenated complex names . I added id='fieldJumlah' for a total, because I didn't use a form

user2977799 Over a year ago

Wow, it's working :) thnx :) I forgot to change name with id in field jumlah the other day :( there's no id before so it did not chnge anything :( but it worked now, thnx :)

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