// to top回到顶部
var
timer =
null;
$(
window).
scroll(
function(){
var
osTop =
$(
document).
scrollTop();
if(
osTop>=
600){
$(
".to_top").
css(
"display",
"block")
}
else{
$(
".to_top").
css(
"display",
"none")
}
});
$(
".to_top").
click(
function(){
timer =
setInterval(
function(){
//设置定时器
var
osTop =
$(
document).
scrollTop();
//获取滚动条高
var
ispeed =
Math.
floor(
osTop/
5);
//ispeed 最后等于0
$(
document).
scrollTop(
osTop-
ispeed);
if(
osTop==(
osTop-
ispeed)){
clearInterval(
timer);
//这里osTop==(osTop-ispeed)即ispeed等于0时 条件成立
timer=
null;
}
},
30);
});