Hi you can do this using bootstrap model popup
for this include bootstrap css and js files and use below code
Your Html Code
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" arialabelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
<h4 class="modal-title" id="myModalLabel">Intorduction</h4>
</div>
<div class="modal-body">
Body Text
</div>
<div class="modal-footer">
<a class="btn btn-default" data-dismiss="modal">Close</a>
</div>
</div>
</div>
</div>
then use this script
<script>
if (localStorage.getItem('showModal')!='yes')
{
localStorage.setItem('showModal','yes');
$('#myModal').modal('show');
}
</script>