function hide_e(id){
  document.getElementById(id).style.display = 'none';	
}

function show_e(id){
  document.getElementById(id).style.display = 'block';	
}
 
<!--
var winWidth = 0;
var winHeight = 0;
function findDimensions() //函数：获取尺寸
{
//获取窗口宽度
if (window.innerWidth)
winWidth = window.innerWidth;
else if ((document.body) && (document.body.clientWidth))
winWidth = document.body.clientWidth;
//获取窗口高度
if (window.innerHeight)
winHeight = window.innerHeight;
else if ((document.body) && (document.body.clientHeight))
winHeight = document.body.clientHeight;
//通过深入Document内部对body进行检测，获取窗口大小
if (document.documentElement  && document.documentElement.clientHeight && document.documentElement.clientWidth)
{
winHeight = document.documentElement.clientHeight;
winWidth = document.documentElement.clientWidth;
}
//结果输出至两个文本框

}
findDimensions();
//调用函数，获取数值
window.onresize=findDimensions; 
//-->

function pop_up(w,h,id){
	WLeft_f2   =   Math.ceil((winWidth   -   w)   /   2  );
    WTop_f2   =   Math.ceil((winHeight   -   h)   /   2   ); 
	if(WTop_f2<0) WTop_f2=10;
	obj_f2 = document.getElementById(id);
    obj_f2.style.left = WLeft_f2 +"px";
    obj_f2.style.top =WTop_f2 +"px";	
}