Hi, is it legal to visit Canada on holiday (British passport) and then whilst in Canada apply for a job and secure a work permit without leaving Canada?

i would also like to know the answer to this.
If it is possible what would the time frame for obtaining a work permit be?
Also is it possible to have a permit to work before entering Canada but without a job.
As in a permit that would allow me to legally find work whilst i am in Canada without the need to apply for a permit after employment was found