打开一个数据库

function openDatabase(dbName) {
  var request = indexedDB.open(dbName);
  request.onsuccess = function (e) {
    var database = request.result;
    if (database) {
      console.log("Database initialized.");
    } else {
      console.error("Database is not initialized!");
    }
    
    //Your code goes here 
    database.close();
  }
  request.onerror = function (e) {
    console.error( e.target.error.message); 
  }
}