You're simply making a post to a url and doing nothing with the response. Where are you expecting your partial view to appear and why? You have to inject the response somewhere on your page.
<select id="CompniesList">
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
<div id="results">
</div>
<script type="text/javascript">
$(document).ready(function () {
$("#CompniesList").on('change', function () {
var id = $(this).val();
var jsonData = { companyId: id };
$.post('/CompanyReceapts/GetReceapts/',
jsonData,
function (response) {
$("#results").html(response);
if (parseInt(id) > 0) {
$('.tblReceapt').show();
}}
);
});
});
</script>