javascript find duplicate Stringin array

Question

javascript find duplicate string in array if there is duplication page not post but after show alert page is post ..so how to avoid 

 

This Is My Code Of Javascript  

 

 

<script>

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

debugger;

var Category1 = $("input[name='[0].Category']").val();

var Category2 = $("input[name='[1].Category']").val();

var Category3 = $("input[name='[2].Category']").val();

var Category4 = $("input[name='[3].Category']").val();

var Category5 = $("input[name='[4].Category']").val();

if (Category1 == "") {

swal("Category Must Be enter");

return false

}

if (Category2 == "") {

swal("Category Must Be enter");

return false

}

if (Category3 == "") {

swal("Category Must Be enter");

return false

}

if (Category4 == "") {

swal("Category Must Be enter");

return false

}

if (Category5 == "") {

swal("Category Must Be enter");

return false

}

//This Is Code For Duplication

 

var names = [Category1, Category2, Category3, Category4, Category5];

 

var uniqueNames = [];

$.each(names, function (i, el) {

e.preventDefault();

if ($.inArray(el, uniqueNames) === -1) {

uniqueNames.push(el);

}

else {

swal("Duplication Not Allow");

return false;

}

});

})

</script>