Could you point how to obtain a modal textbox value when a modal is open?

Maybe show us the HTML and other parts of this script?  

The NaN is a JavaScript indicator of Not-a-Number.  You can get this from some arithmetic operations such as dividing by zero or using non-numeric values in arithmetic.

Of course

Modal View code (partial):

<div id="view" class="modal fade" tabindex="-1" role="dialog">
		<div class="modal-dialog modal-width-projeto">
			<div class="modal-content">
				<!-- Begin: Modal Header -->
				<div class="modal-header bg-info bg-projeto">
					<button type="button" class="close" data-dismiss="modal" aria-label="Close">
						<span aria-hidden="true">×</span>
					</button>
					<h4 class="modal-title">
						<i class="mr10 fa fa-building"></i>
						<span>Reclamação</span>
					</h4>
				</div>
				<!-- End: Modal Header -->
				<!-- Beign: Modal Body -->
				<div class="modal-body modal-body-projeto">
					<div class="panel panel-projeto mt-10">
						<!-- Begin: Form Edit -->
						<form method="post" action="#" id="entity-form" enctype="multipart/form-data">
							<input type="hidden" class="id_reclamacao" name="id_reclamacao" value="">

							<div class="panel-body panel-body-projeto p10 pb10 tab-content pn br-n admin-form">
								<!-- Begin: Campos -->
								<div class="row">
									<!-- Seguradora -->
									<div class="col-xs-12 mb15">
										<label for="fk_seguradora" class="field-label text-muted mb10">Cliente Corporativo</label>
										
										<label for="fk_seguradora" id="fk_seguradora" class="validar field select">
											<?php echo $fk_seguradora;?>
											<i class="arrow double"></i>
										</label>
									</div>
								</div>
								<div class="row">
									<!-- Data -->
									<div class="col-xs-4 mb15">
										<label for="data" class="field-label text-muted mb10">Data</label>
										<label for="data" class="validar field select">
											<input type='text'id='data' name='data' class="form-control gui-input br-light light" placeholder=""/>
										</label>
									</div>

...

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The jQuery code as informed before.

You have a disconnect in what you have shown us
JQuery

$('#edit').on('show.bs.modal', function () {

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Dialog

<div id="view" class="modal fade" tabindex="-1" role="dialog">

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view != edit

Sorry....

<div id="edit" class="modal fade" tabindex="-1" role="dialog">
		<div class="modal-dialog modal-width-projeto">
			<div class="modal-content">
				<!-- Begin: Modal Header -->
				<div class="modal-header bg-info bg-projeto">
					<button type="button" class="close" data-dismiss="modal" aria-label="Close">
						<span aria-hidden="true">×</span>
					</button>
					<h4 class="modal-title">
						<i class="mr10 fa fa-building"></i>
						<span>Reclamação</span>
					</h4>
				</div>
				<!-- End: Modal Header -->
				<!-- Beign: Modal Body -->
				<div class="modal-body modal-body-projeto">
					<div class="panel panel-projeto mt-10">
						<!-- Begin: Form Edit -->
						<form method="post" action="#" id="entity-form" enctype="multipart/form-data">
							<input type="hidden" class="id_reclamacao" name="id_reclamacao" value="">

							<div class="panel-body panel-body-projeto p10 pb10 tab-content pn br-n admin-form">
								<!-- Begin: Campos -->
								<div class="row">
									<!-- Seguradora -->
									<div class="col-xs-12 mb15">
										 <label for="fk_seguradora" class="field-label text-muted mb10">Cliente Corporativo</label>
										 <label for="fk_seguradora" class="validar field select">
											<?php echo $fk_seguradora;?>
											<i class="arrow double"></i>
										</label>
									</div>
								</div>
								<div class="row">
									<!-- Data -->
									<div class="col-xs-4 mb15">
										<label for="data" class="field-label text-muted mb10">Data</label>
										<label for="data" class="validar field select">
											<input type='text'id='data' name='data' class="form-control gui-input br-light light" placeholder=""/>
										</label>
									</div>

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Screenshot below

Thanks for assistance!

You are welcome.