function castling()
{
	document.getElementById('div_top').style.position = 'absolute';
	document.getElementById('div_top').style.left = '0';
	document.getElementById('div_top').style.top = '0';
	document.getElementById('div_central').style.position = 'absolute';
	document.getElementById('div_central').style.left = '0';
	document.getElementById('div_central').style.top = document.getElementById('div_top').clientHeight+'px';
	document.getElementById('div_bottom').style.position = 'absolute';
	document.getElementById('div_bottom').style.left = '0';
	document.getElementById('div_bottom').style.top = document.getElementById('div_top').clientHeight+document.getElementById('div_central').clientHeight+'px';
}
function movbottom()
{
	document.getElementById('div_bottom').style.position = 'absolute';
	document.getElementById('div_bottom').style.left = '0';
	document.getElementById('div_bottom').style.top = document.getElementById('div_top').clientHeight+document.getElementById('div_central').clientHeight+'px';
}