There is no one size fits all answer to this question. Ultimately the answer is entirely based on your own personal financial situation.
What you need to know is that creating a real online business that will provide consistent monthly income will take a lot longer than you might imagine. So, while in the online business creation phase there is no income.
The last thing you want is to build an online business while worrying about how you are to survive financially. So, unless you can afford to pay your bills, purchase your necessities, and keep a roof over your head without the income that your job provides then I say NO do not quit your day job.