var imgheight;
window.screen.width>800 ? imgheight=100:imgheight=100; //距离页面底部的高度

function mymove(obj,position,imgheight)
{
	var o = eval(obj);
	o.style.top=document.body.scrollTop+document.body.offsetHeight-imgheight;
	if (position)
		o.style.left=5;
	else
		o.style.right=5;
	setTimeout("mymove(" + obj.id + "," + position + "," + imgheight + ");",50);
}