Check Duplicate Value by Table Row

var contents = {};
var duplicates = false;

$('table tbody tr').each(function () {
 var tdContent = $(this).children('input').val();
 if (contents[tdContent]) {
  duplicates = true;
  return false;
 }
 contents[tdContent] = true;
});

if (duplicates) {
 console.log('duplicate');
}