<!DOCTYPE html> <meta charset="utf-8"> <title>IDBDatabase.createIndex() - If an index with the name name already exists in this object store, the implementation must throw a DOMException of type ConstraintError </title> <link rel="author" title="Intel" href="http://www.intel.com"> <link rel="help" href="https://dvcs.w3.org/hg/IndexedDB/raw-file/tip/Overview.html#widl-IDBObjectStore-createIndex-IDBIndex-DOMString-name-DOMString-sequence-DOMString--keyPath-IDBIndexParameters-optionalParameters"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="support.js"></script> <div id="log"></div> <script> var t = async_test(), open_rq = createdb(t); open_rq.onupgradeneeded = function (e) { var db = e.target.result; var ostore = db.createObjectStore("store"); ostore.createIndex("a", "a"); assert_throws("ConstraintError", function(){ ostore.createIndex("a", "a"); }); t.done(); } </script>