Software engineers, I (2 years experience) want to switch my domain from firmware to web development. Is it okay to give resignation letter to my current employer without having another offer at hand?

Currently I am not able to give much time in learning web development. But I fear to resign without having a new job offer at hand. My family can live without my salary. But there will be pressure if I dont get a job in 2-3 months after I quit. I dont like my current job, employer. I want to leave this place as early as possible. Have you been in this similar situation? What actions did you take? What can I do?