<?php $prevURLPATH=urlencode($p); echo form_open('form/'.$usr.'/'.$name.'?prevURL='.$p); ?>


<div class="form-group row">
<label class="col-md-3 control-label text-center"></label>
<div class="col-md-8">
<button id="submit-upload-form" class="btn btn-primary btn-tw" onclick="setup(); return false;"><i class="glyphicon glyphicon-upload"></i>Submit</button>
<button id="validate" hidden="true" type="submit"></button>
</div>
</div>


function setup()
{ .......Checking some fields in the form...............}

// view
echo form_open('basic_controller/submission');
echo form_input( array('name'=>'text', 'id'=>'text_input') );
echo form_submit('my_submit', 'Enter', "id='my_submit'");
echo form_close();

// controller
function submission() {
    $field = $this->input->post('text');
    // add your checkings (backend)
}

// view
    <script type='text/javascript'>
        $(document).on('click', '#my_submit', function() {
            var input_value = $('#text_input').val();

            // do your frontend checkings here
            alert('before form submission. ' + input_value);
        });
    </script>

$(document).on('click', '#submit-upload-form', function() {
    setup();
});

<input type="file" name="pic" id="pic" accept="image/gif, image/jpeg" required/>

<script>
$("#your_form").validate();
</script>

<?php
$attributes = array('class' => 'email', 'id' => 'myform');
$prevURLPATH=urlencode($p); echo form_open('form/'.$usr.'/'.$name.'?prevURL='.$p,$attributes); ?>
<div class="form-group row">
<label class="col-md-3 control-label text-center"></label>
<div class="col-md-8">
<button id="submit-upload-form" class="btn btn-primary btn-tw" type="submit"><i class="glyphicon glyphicon-upload"></i>Submit</button>
</div>
</div>
<script>
$(document).ready(function(){
    $('#myform').submit(function() {
         alert('hi');
        //write your validation code here. and make sure about jquery library is loaded.
        return false;
    });
}};
</script>

<script src="<?php echo YOUT_PATH.'jquery-1.12.2.js'; ?>"></script>
<script src="<?php echo YOUR_PATH.'bootstrap.min.js'; ?>"></script>
<script src="<?php echo YOUT_PATH.'jquery-validation-1.15.0/dist/jquery.validate.js'; ?>"></script>

<?php echo form_open('form/'.$usr.'/'.$name.'?prevURL='.urlencode($p), array('class'=>'form-horizontal','class'=>'signupForm')); ?>
<div class="form-group">
  <div class="col-sm-9 col-sm-offset-4">
    <label class="col-md-3 control-label text-center"></label>
    <button type="submit" class="btn btn-primary btn-tw" name="signup" ><i class="glyphicon glyphicon-upload"></i>Submit</button>
  </div>
</div>
<?php form_close(); ?>

<script type="text/javascript">
$( "#signupForm" ).validate( {
  rules: {
    // Rules Here
  },
  messages: {
    // Messages here
  },
  errorElement: "em",
  errorPlacement: function ( error, element ) {
    // Add the `help-block` class to the error element
    error.addClass( "help-block" );

    if ( element.prop( "type" ) === "checkbox" ) {
      error.insertAfter( element.parent( "label" ) );
    } else {
      error.insertAfter( element );
    }
  },
  highlight: function ( element, errorClass, validClass ) {
    $( element ).parents( ".col-sm-5" ).addClass( "has-error" ).removeClass( "has-success" );
  },
  unhighlight: function (element, errorClass, validClass) {
    $( element ).parents( ".col-sm-5" ).addClass( "has-success" ).removeClass( "has-error" );
  }
});
</script>

<form id="formId" action="path">HTML</form>
<script>
$("#formId").submit(function(){
  //validation
  return false;
});
<script>

<form  action="path" id="formId"></form>

<?php $prevURLPATH=urlencode($p); echo form_open('form/'.$usr.'/'.$name.'?prevURL='.$p); ?>


<div class="form-group row">
<label class="col-md-3 control-label text-center"></label>
<div class="col-md-8">
<button id="submit-upload-form" class="btn btn-primary btn-tw" onclick="setup(); return false;"><i class="glyphicon glyphicon-upload"></i>Submit</button>
<button id="validate" hidden="true" type="submit"></button>
</div>
</div>
</form>

<script>
function setup()
{ .......Checking some fields in the form...............}
</script>

<button id="submit-upload-form" class="btn btn-primary btn-tw" onclick="setup(); return false;"><i class="glyphicon glyphicon-upload"></i>Submit</button>

function setup(){
  //do your verification stuff
  if (valid){
    $("#yourFormId").submit();
  }

}