From http://code.tutsplus.com/tutorials/working-with-indexeddb--net-34673
Check if indexedDB is supported in this browser
document.addEventListener("DOMContentLoaded", function(){
if("indexedDB" in window){
console.log("YES!!! I CAN DO IT!!! WOOT!!!");
}else{
console.log("I has a sad.");
}
}, false);