I'm definitely the type of person to get to know my characters the more I write them. Sure, I may start with a character sheet with design ideas, some adjectives for their personality, and some blurbs about their backstory, but I don't actually feel like I know them.
As far as my 'script' goes, it's basically just major turns or checkpoints of the story that I'm like 95% sure that I'm going to go through with to carry on the story, but for everything in between these points, it's all up to the flow of the writing. That flow is what helps me get to know my characters.
Heck, I didn't really have any romance planned, but at the rate my drafts are going, the characters are basically working that into their stories themselves.