If you want to show a div after scrolling a number of pixels:
100
$(document).scroll(function() {
var y = $(this).scrollTop();
if (y > 800) {
$('.bottomMenu').fadeIn();
} else {
$('.bottomMenu').fadeOut();
}
});
$(document).scroll(function() {
var y = $(this).scrollTop();
if (y > 800) {
$('.bottomMenu').fadeIn();
} else {
$('.bottomMenu').fadeOut();
}
});
body {
height: 1600px;
}
.bottomMenu {
display: none;
position: fixed;
bottom: 0;
width: 100%;
height: 60px;
border-top: 1px solid #000;
background: red;
z-index: 1;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>Scroll down... </p>
<div class="bottomMenu"></div>
这很简单，但很有效.
Documentation for .scroll()
Documentation for .scrollTop()
If you want to show a div after scrolling a number of pixels,
没有jQuery:
Working Example
myID = document.getElementById("myID");
var myScrollFunc = function() {
var y = window.scrollY;
if (y >= 800) {
myID.className = "bottomMenu show"
} else {
myID.className = "bottomMenu hide"
}
};
window.addEventListener("scroll", myScrollFunc);
myID = document.getElementById("myID");
var myScrollFunc = function() {
var y = window.scrollY;
if (y >= 800) {
myID.className = "bottomMenu show"
} else {
myID.className = "bottomMenu hide"
}
};
window.addEventListener("scroll", myScrollFunc);
body {
height: 2000px;
}
.bottomMenu {
position: fixed;
bottom: 0;
width: 100%;
height: 60px;
border-top: 1px solid #000;
background: red;
z-index: 1;
transition: all 1s;
}
.hide {
opacity: 0;
left: -100%;
}
.show {
opacity: 1;
left: 0;
}
<div id="myID" class="bottomMenu hide"></div>
Documentation for .scrollY
Documentation for .className
Documentation for .addEventListener
If you want to show an element after scrolling to it:
Working Example
$('h1').each(function () {
var y = $(document).scrollTop();
var t = $(this).parent().offset().top;
if (y > t) {
$(this).fadeIn();
} else {
$(this).fadeOut();
}
});
$(document).scroll(function() {
//Show element after user scrolls 800px
var y = $(this).scrollTop();
if (y > 800) {
$('.bottomMenu').fadeIn();
} else {
$('.bottomMenu').fadeOut();
}
// Show element after user scrolls past
// the top edge of its parent
$('h1').each(function() {
var t = $(this).parent().offset().top;
if (y > t) {
$(this).fadeIn();
} else {
$(this).fadeOut();
}
});
});
body {
height: 1600px;
}
.bottomMenu {
display: none;
position: fixed;
bottom: 0;
width: 100%;
height: 60px;
border-top: 1px solid #000;
background: red;
z-index: 1;
}
.scrollPast {
width: 100%;
height: 150px;
background: blue;
position: relative;
top: 50px;
margin: 20px 0;
}
h1 {
display: none;
position: absolute;
bottom: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>Scroll Down...</p>
<div class="scrollPast">
<h1>I fade in when you scroll to my parent</h1>
</div>
<div class="scrollPast">
<h1>I fade in when you scroll to my parent</h1>
</div>
<div class="scrollPast">
<h1>I fade in when you scroll to my parent</h1>
</div>
<div class="bottomMenu">I fade in when you scroll past 800px</div>
请注意，不能将元素的偏移量设置为display: none;，取而代之的是元素父元素的偏移量.
Documentation for .each()
Documentation for .parent()
Documentation for .offset()
If you want to have a nav or div stick or dock to the top of the page once you scroll to it and unstick/undock when you scroll back up:个
100
$(document).scroll(function () {
//stick nav to top of page
var y = $(this).scrollTop();
var navWrap = $('#navWrap').offset().top;
if (y > navWrap) {
$('nav').addClass('sticky');
} else {
$('nav').removeClass('sticky');
}
});
#navWrap {
height:70px
}
nav {
height: 70px;
background:gray;
}
.sticky {
position: fixed;
top:0;
}
$(document).scroll(function () {
//stick nav to top of page
var y = $(this).scrollTop();
var navWrap = $('#navWrap').offset().top;
if (y > navWrap) {
$('nav').addClass('sticky');
} else {
$('nav').removeClass('sticky');
}
});
body {
height:1600px;
margin:0;
}
#navWrap {
height:70px
}
nav {
height: 70px;
background:gray;
}
.sticky {
position: fixed;
top:0;
}
h1 {
margin: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>Zombie ipsum reversus ab viral inferno, nam rick grimes malum cerebro. De carne lumbering animata corpora quaeritis. Summus brains sit, morbo vel maleficia? De apocalypsi gorger omero undead survivor dictum mauris. Hi mindless mortuis soulless creaturas,
imo evil stalking monstra adventus resi dentevil vultus comedat cerebella viventium. Qui animated corpse, cricket bat max brucks terribilem incessu zomby. The voodoo sacerdos flesh eater, suscitat mortuos comedere carnem virus. Zonbi tattered for solum
oculi eorum defunctis go lum cerebro. Nescio brains an Undead zombies. Sicut malus putrid voodoo horror. Nigh tofth eliv ingdead.</p>
<div id="navWrap">
<nav>
<h1>I stick to the top when you scroll down and unstick when you scroll up to my original position</h1>
</nav>
</div>
<p>Zombie ipsum reversus ab viral inferno, nam rick grimes malum cerebro. De carne lumbering animata corpora quaeritis. Summus brains sit, morbo vel maleficia? De apocalypsi gorger omero undead survivor dictum mauris. Hi mindless mortuis soulless creaturas,
imo evil stalking monstra adventus resi dentevil vultus comedat cerebella viventium. Qui animated corpse, cricket bat max brucks terribilem incessu zomby. The voodoo sacerdos flesh eater, suscitat mortuos comedere carnem virus. Zonbi tattered for solum
oculi eorum defunctis go lum cerebro. Nescio brains an Undead zombies. Sicut malus putrid voodoo horror. Nigh tofth eliv ingdead.</p>