event.preventDefault not working when condition true

Question

when condition false event.preventDefault working but when condition true event.preventDefault not submit page.

 

This Is My Code:- 

 

<script>

$("#category").on('submit', function (event) {

event.preventDefault ? event.preventDefault() : event.returnValue = false;

var url = '@Url.Action("CheckCategory_Name", "CategoryAndSubCategory")';

$.getJSON(url, { Category1: Category1, Category2: Category2, Category3: Category3, Category4: Category4, Category5: Category5 }, function (data) {

debugger;

if (data.isDuplicate != true) {

$("#category").submit();

return true;

}

else {

swal("The Category Name Is Already Exist");

return false;

}

});

 

});

</script>