Div highly adaptive

Today, I handled a problem of Div height self-adaptation... record...

The effect is that head and foot are fixed, and the content DIV in the middle is highly adaptive...

 <!  Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"  >      <  Html  Xmlns  = "Http://www.w3.org/1999/xhtml"  Lang  = "ZH-CN"  >      <  Head  >     <  Title  > </  Title  >      <  Style  Type  = "Text/CSS"  >  HTML, body  {  Margin  :  0 ;  Padding  :  0  ;          }      </  Style  >      </  Head  >      <  Body  >         <  Div  Style  = "Height: 100px; position: fixed; width: 400px; Background-color: Gray; top: 0 ;"  > <  H1  > This is top </  H1  > </  Div  >           <  Div  Style = "Float: Left; width: 400px; position: absolute; overflow-Y: Scroll; overflow-X: hidden; Background-color: green; top: 100px; bottom: 100px ;"  >                   <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  /> Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  < BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  /> Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  < BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  /> Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  < BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa <  BR  />  Aaaaaaaaaaaaaaaaaaaa  <  BR  />  Aaaaaaaaaaaaaaaaaaaa  </  Div  >          <  Div  Style  = "Height: 100px; position: fixed; width: 400px; Background-color: Gray; bottom: 0 ;" > <  H1  > This is bottom </  H1  > </  Div  >      </  Body  >      </  Html  >   

The effect is that the content div is highly adaptive.