hi...I checked courselab 2.7 lessons on all browsers and also on ipad ..all worked fine...but but galaxy tabs dont even show anything...do you know anything about it? do we need any app to install on galaxy...

Hi Ilker, galaxy tab is the Galaxy tablet ??
First which version tablet and Android is this, I'd figure maybe a 10.1 revision.
Next which browser are you trying to use?
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I have heard there are real problems with anything but dolphin.
You MUST have JS enabled or the API won't work.
This is an Android/Dolphin issue, it might be worth while posting on the android and dolphin forums.