Cannot sign into iCloud from iPad using Safari

I have setup an Apple ID with my iPad 2 and also turn on iCloud in the setting. When I try to sign into my iCloud account at iCloud.com using iPad's safari app, it tells me to establish an account on my iPad. But the iCloud is working on my device.The iCloud.com website is only for accessing iCloud on a browser from your Mac/PC. It's useless on an iOS device.