У вашего броузера проблема в совместимости с HTML5
I had a question this week asking ways to count files in Linux. Whilst the solution can be quite simple with ls and wc. There are interesting options with ls -a ls -A and also find. Invest 5 minutes of your life in this video
Additionally you can find my video courses on Pluralsight: http://pluralsight.com/training/Authors/Details/andrew-mallett and take time to see my own site http://www.theurbanpenguin.com