Safari keeps warning "malicious javascript detected on this domain"
JavaScript of Baidu Ad and Statistics are redirected to GitHub urls https://github.com/greatfire/ and https://github.com/cn-nytimes/ It is in fact DDoS due to large population. 
GitHub returns an alert page in order to stop the recursive JS running for each user. 
This is possibly done by GFW (Great Fire Wall) as the two URLs are not welcomed by them and only people outside mainland China faced this issue today. (GitHub cannot function well in China).
A detailed analysis can be found on WooYun (in Simplified Chinese)
http://drops.wooyun.org/papers/5398