var goto_top_type = -1;
var goto_top_itv = 0;
 
function goto_top_timer()
{
var y = goto_top_type == 1 ? document.documentElement.scrollTop : document.body.scrollTop;
var moveby = 15;
 
y -= Math.ceil(y * moveby / 100);
if (y < 0) {
y = 0;
}
 
if (goto_top_type == 1) {
document.documentElement.scrollTop = y;
}
else {
document.body.scrollTop = y;
}
 
if (y == 0) {
clearInterval(goto_top_itv);
goto_top_itv = 0;
}
}
 
function goto_top()
{
if (goto_top_itv == 0) {
if (document.documentElement && document.documentElement.scrollTop) {
goto_top_type = 1;
}
else if (document.body && document.body.scrollTop) {
goto_top_type = 2;
}
else {
goto_top_type = 0;
}
 
if (goto_top_type > 0) {
goto_top_itv = setInterval('goto_top_timer()', 20);
}
}
}

var timer
//设置每10毫秒执行一次 scrollit 的函数 
function init(){timer=setInterval("scrollit()",20);}  
function stopit(){clearInterval(timer)}
function scrollit(){        
  scrollBy(0,1);              
if(document.body.scrollTop==document.body.scrollHeight)  
     stop();
}
	document.onmousedown=stopit;
	document.ondblclick=init;
	
function copyUrl()
   { 
    var clipBoardContent=this.location.href; 
    window.clipboardData.setData("Text",clipBoardContent); 
    alert("复制本页地址成功!"); 
   }