Preventing modal window when the page is refreshing

I have a modal window (bootstrap 4) with on load function on my web page. Also I have a multipage gridview. When I open my web page modal window shows and there is no problem. But, when I click next page on gridview, page refreshes and modal window shows again. How to prevent showing modal window second time. Thanks in advance.

<script type="text/javascript">
$(window).on('load',function(){
    $('#myModal').modal('show');
});