can someone apply a visa in hong kong if he enters there (HK)as a non-visa holder?

It is impossible for you to get a China visa in Hong Kong if it is the first time for you to go to China. You'd better apply for China visa in the Philippines. It is possible to get a SINGLE entry China visa valid for 15 Days in HK, provided that all your documents are upto date: that u have previously travelled to china on a valid visa before; ur passport has no cancelled china visas and that you have a confirmed return ticket or a ticket showing exit from China and a confirmed hotel booking voucher