Nice job on this. And as Yahoo fails who knows what will happen to Yahoo Finance, so potentially very good timing too.

One piece of feedback for the charts: being able to see the % up/down (over the dates selected) not just prices would be helpful.

For example: in the case of comparing two stocks (or a stock to an index) performance YTD, seeing just prices doesn't mean much, % change (eg +5% vs +10% YTD) is what is being compared.