What are the main differences (if any) between the box models of IE8 and Firefox3?
Are they the same now?
What are the other main differences between these two browsers? Can a web developer assume that these two browsers as the same since they (seem to) support the latest web standards?
The Internet Explorer box model has been ‘fixed’ since Internet Explorer 6 so long as your pages are in standard compliants mode.
See: Quirks mode and Internet Explorer box model bug.
Until I learnt about doctype declerations getting IE to work properly was a real PAIN, because IE runs in ‘quirks mode’ by default. So having a standards mode doctype will eliminate a whole bunch of the most painful CSS problems.