How to use remaining width?

[pay4m]

I'd like to have div2 horizontally aligned right of div1. Div2 should also stretch the remaining width, which is a variable number (browser width). If I set div2 width to something absolute (300px), I get the correct alignment but lose consuming the remaining width. How should this be done?\[code\]<div id="1" style="float:left;width:100px"> the first box</div><div id="2" style="float:left;width:100%"> the second box</div>\[/code\]