We're looking for a person or people to help audit MDN to find places we could speed up. Is this you or someone you know? Check out the RFP: https://mzl.la/2IHcMiE


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.


var lowerOpen = myKeyRange.lowerOpen


A boolean:

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 = event.target.result;
      if(cursor) {
        var listItem = document.createElement('li');
        listItem.innerHTML = '<strong>' + cursor.value.fThing + '</strong>, ' + cursor.value.fRating;
      } else {
        console.log('Entries all displayed.');


Specification Status Comment
Indexed Database API
The definition of 'lowerOpen' in that specification.
Indexed Database API 2.0
The definition of 'lowerOpen' in that specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support


23 — 24 webkit



10 — 16 moz

FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes ?22228 ?

1. partial

See also

Document Tags and Contributors

 Contributors to this page: fscholz, jpmedley, arronei, libbymc, chrisdavidmills
 Last updated by: fscholz,