01.
<script src=
"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"
></script>
02.
<script>
03.
$(
function
(){
04.
05.
06.
var
scroll_top = $(
"<a id='scroll_top'>▲</a>"
)
07.
scroll_top.prop(
"href"
,
"javascript:void(0)"
);
08.
scroll_top.css({
09.
"position"
:
"fixed"
,
10.
"text-decoration"
:
"none"
,
11.
"font-size"
:
"40px"
,
12.
"color"
:
"rgba(255,255,255,0.85)"
,
13.
"text-shadow"
:
"1px 1px 2px #656a6f"
,
14.
"right"
:
"0.5%"
,
15.
"bottom"
:
"5rem"
,
16.
"display"
:
"none"
17.
});
18.
19.
20.
scroll_top.on(
"click"
,
function
(){
21.
window.scroll(0,0);
22.
});
23.
24.
25.
$(
"body"
).append( scroll_top );
26.
27.
28.
$(window).on(
"scroll"
,
function
(){
29.
var
scroll = $(
"html"
).scrollTop();
30.
if
( scroll <= 200 && $(
"#scroll_top"
).css(
"display"
) !=
"none"
) {
31.
$(
"#scroll_top"
).css(
"display"
,
"none"
);
32.
}
33.
if
( scroll > 200 && $(
"#scroll_top"
).css(
"display"
) ==
"none"
) {
34.
$(
"#scroll_top"
).css(
"display"
,
""
);
35.
}
36.
});
37.
38.
});
39.
</script>