***关于父母旅游延期,我帮父母填申请表I539可以网上提交吗？
-Depends. If your parents only want to file one I-539 for boith (i.e. one I-539 plus I-539A and pay one I-539 filing fee), then they have to file it by paper. If they file I-539 separately, then they can fie it online individually.
因为我看网站写着如果需要律师等，不能网络提交。那我自己不是律师可以作为Preparer的话可以网上提交吗？
-Yes.
***网站上问“When does your current nonimmigrant status expire?”这里是问B2的签证页有效期还是I94的有效期？
-It is I-94 expiration date.
****父母资金证明如何提供？可以用我的银行资料吗？
-Yes, but you need to provide I-134 with the support documents such as your employment verification letter, W2, copies of W2 and tax return, bank statement (if you want to use the savings for your parents).
