i have some code for validation phone number with prefix validation. i want to validate from first digit and so on up to four digits. example:

first digit  

0 => valid   

second digit  

8 => valid   

third digit  

1 => valid  

2 => valid  

3-9 => invalid  

four digit  

7 => valid  

8 => valid  

9 => valid  

1-6 => invalid

is it possible to validating like that with regex?

i have regex code  

```
/^08(17|18|19|31|32|33|38|59|77|78)[0-9]{0,8}$/

```

but not validating from first digit. please help me

Here's my php code:

```
    <div class="container">
        <div style="width:601px; height: 487px;position: fixed;">
            <div style="background-image: url(xlimages/20160614_XL_elemenVisual_-02_cropped.png); background-size: 600px 563px;">
            <div style="height:563px;">
                <center>
<h2 style="color: white; padding-top: 32px; font-size: 50px; font-family: "Gotham Bold";"><b>Masukkan No. XL/Axis</b></h2>
                        <form action="<?php echo $_SERVER[PHP_SELF]; ?>" method="POST">
                            <div style="margin-top:70px;">
                                <div class="input-control">
                                    <br/>
                                    <input type="text" name="msidn" id="jkeyboard" onlick="$('#pwd').replaceSelection("", true);" min="1" style="font-weight: bold; width:500px; height: 70px; border-color:#1ba1e2; color: #1ba1e2; font-size: 30px; text-align: center; line-height: 75px;" required>
                                </div>
                                <input type="hidden" name="cmd" value="cek"><br/><br/><br/><br/><br/><span id="spnPhoneStatus"></span>
                                <div style="margin-top: 190px;"><b>
<input type="submit" onclick="document.getElementById('sound1').play();" name="sbm" value="Lanjut" style="margin-bottom: 6px;background: #1ba1e2; border-color: #1ba1e2; height: 70px; font-weight: bold;  margin-left:0px; width:280px; font-size: 30px;" class="button primary">
                                </b><br/><br/><br/>
                                </div>
                            </div>
                        </form>
                </center>
                </div>
            </div>
        </div>
    </div>

```

and here is my javascript code:

```
    <script>
$(document).ready(function() {
  $('#jkeyboard').blur(function(e) {
    if (validatePhone('jkeyboard')) {
      $('#spnPhoneStatus').html('Nomor Yang Anda Masukkan No. XL/Axis');
      $('#spnPhoneStatus').css('color', 'green');
    } else {
      $('#spnPhoneStatus').html('Nomor Yang Anda Masukkan Bukan No. XL/Axis');
      $('#spnPhoneStatus').css('color', 'red');
    }
  });
});

function validatePhone(jkeyboard) {
  var a = document.getElementById(jkeyboard).value;
  var filter = /^08(17|18|19|31|32|33|38|59|77|78)[0-9]{0,8}$/;
  if (filter.test(a)) {
    return true;
  } else {
    return false;
  }
}

</script>

```