Hi, there’s nothing like that build in for the current version but it’s a popular request for a ‘larger map’ link, so it’s on my development list.
For example, if the map’s name is ‘mapp0’ the div has the same name so you could just set the width and height for div mapp0. After you resize the div, call mapp0.resize() to notify the map that the container size has changed. The FAQ has details about setting a map name.
var mydiv = getElementById('mapp0'); mydiv.style.width = "100%"; mydiv.style.height = "100%"; mapp0.resize();