Fixed + Input bug phenomenon under iOS

<Bodyclass="Layout-scroll-fixed" >
 <!--fixed-positioned head-to-
 <Header>
 
 </Header>
 
 <!--areas that can be scrolled--
 <Main>
 <Div Class="Content">
 <!--content here ...-
 </Div>
 </Main>
 
 <!--fixed positioning at the bottom---
 <Footer>
 <Input Type="Text" Placeholder="Footer ..."/>
 <button Class="Submit"> Submit   </button>
  </footer>
</body>

HeaderFooterMain{
 DisplayBlock
}

Header{
 PositionFixed
 Height 50px;
 Left 0;
 Right 0;
 Top 0;
}

Footer{
 PositionFixed
 Height 34px;
 Left 0;
 Right 0;
 Bottom 0;
}

Main{
 /* Main is absolutely positioned for internal scrolling */
 position: Absolute 
  top: 50px; 
  bottom: 34PX; 
  /* so that it can scroll */
  overflow-y: scroll; 
 } 
 Note: Note Using elastic scrolling           

Fixed + Input bug behavior under iOS