The lowerOpen read-only property of the IDBKeyRange interface returns a boolean indicating whether the lower-bound value is included in the key range.

Note: This feature is available in Web Workers


A boolean value:

Value Indication
true The lower-bound value is not included in the key range.
false The lower-bound value is included in the key range.


The following example illustrates how you'd use a key range. Here we declare keyRangeValue = IDBKeyRange.upperBound("F", "W", true, true); — a range that includes everything between "F" and "W" but not including them — since both the upper and lower bounds have been declared as open (true). We open a transaction (using IDBTransaction) and an object store, and open a Cursor with IDBObjectStore.openCursor, declaring keyRangeValue as its optional key range value.

After declaring the key range, we log its lowerOpen property value to the console, which should appear as "true": the lower bound is open, so won't be included in the range.

Note: For a more complete example allowing you to experiment with key range, have a look at our IDBKeyRange-example repo (view the example live too.)

function displayData() {
  var keyRangeValue = IDBKeyRange.bound("F", "W", true, true);

  var transaction = db.transaction(['fThings'], 'readonly');
  var objectStore = transaction.objectStore('fThings');

  objectStore.openCursor(keyRangeValue).onsuccess = function(event) {
    var cursor =;
      if(cursor) {
        var listItem = document.createElement('li');
        listItem.innerHTML = '<strong>' + cursor.value.fThing + '</strong>, ' + cursor.value.fRating;

      } else {
        console.log('Entries all displayed.');


Indexed Database API 3.0
# ref-for-dom-idbkeyrange-loweropen①

Browser compatibility

BCD tables only load in the browser

See also