$('.btnNext').click(function() {
  $('.nav-pills > .active').next('li').find('a').trigger('click');
});

$('.btnPrevious').click(function() {
  $('.nav-pills > .active').prev('li').find('a').trigger('click');
});

//  Bind the event handler to the "submit" JavaScript event
$('#validateFirst').click(function() {

  // Get the Login Name value and trim it
  var name = $.trim($('#admission_no').val());

  // Check if empty or not
  if (name === '') {
    alert('Admission No. field is empty.');
    return false;
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

<ul class="nav nav-pills nav_content">
  <li class="active"><a data-toggle="pill" href="#admission">Admission Details</a></li>
  <li><a data-toggle="pill" href="#personal">Personal Details</a></li>
  <li><a data-toggle="pill" href="#family">Family Details</a></li>
</ul>

<form id="form1" action="<?php echo site_url('student/create') ?>" id="employeeform" name="employeeform" method="post" accept-charset="utf-8" enctype="multipart/form-data">
  <div class="tab-content">
    <div id="admission" class="tab-pane fade in active">
      <div class="row">
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">Admission Number *</label>
            <input id="admission_no" name="admission_no" placeholder="" type="text" class="form-control" value="admission_no" />
          </div>
        </div>
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">Application Number  *</label>
            <input id="application_no" name="application_no" placeholder="" type="text" class="form-control" value="application_no" />
          </div>
        </div>
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">Academic Year  *</label>
            <input id="academic_year" name="academic_year" placeholder="" type="text" class="form-control" value="academic_year" />
          </div>
        </div>
      </div>
      <a class="btn btn-primary btnNext pull-right" id="validateFirst">Next</a>
    </div>
    <div id="personal" class="tab-pane fade">
      <div class="row">
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">First Name *</label>
            <input id="firstname" name="firstname" placeholder="" type="text" class="form-control" value="firstname" />
          </div>
        </div>
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">DOB *</label>
            <input id="dob" name="dob" placeholder="" type="text" class="form-control" value="DOB" readonly="readonly" />
          </div>
        </div>
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputFile">Address  *</label>
            <textarea id="student_address" name="student_address" placeholder="" class="form-control" rows="2"></textarea>
          </div>
        </div>
      </div>
      <a class="btn btn-primary btnPrevious pull-left">Previous</a>
      <a class="btn btn-primary btnNext pull-right">Next</a>
    </div>
    <div id="family" class="tab-pane fade">
      <div class="row">
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">Father Name *</label>
            <input id="father_name" name="father_name" placeholder="" type="text" class="form-control" value="father_name" />
          </div>
        </div>
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">Father Occupation *</label>
            <input id="father_occupation" name="father_occupation" placeholder="" type="text" class="form-control" value="father_occupation" />
          </div>
        </div>
        <div class="col-md-3">
          <div class="form-group">
            <label for="exampleInputEmail1">Mother Name *</label>
            <input id="mother_name" name="mother_name" placeholder="" type="text" class="form-control" value="mother_name" />
          </div>
        </div>
      </div>
      <a class="btn btn-primary btnPrevious pull-left">Previous</a>
      <button type="submit" class="btn btn-info pull-right">Save</button>
    </div>
  </div>
</form>