[我试图弄清楚如何通过下面的脚本在传递周围的容器#box时开始计算不透明度,而不是在页面的顶部开始计算不透明度。
有人知道吗?
脚本:
function parallaxFade() {
scrollPos = $(this).scrollTop();
$('#boxtext').css({
'opacity': 1-(scrollPos/100)
});
}
HTML:
<div class="box" id="box">
<h3 class="boxtext" id="boxtext">Heading</h3>
</div>
我们可以将滚动位置(此处为ScrollPos)与使用jQuery position()获得的#box位置进行比较。视觉效果在这里不会被提及,因此我将其保留为演示目的。这很令人困惑,因此,如果您需要在#box容器之后严格更改不透明度,可以将条件更改为:
if (scrollPos > pos+$('#box').height()) {
function parallaxFade(pos) {
var opa = $('#boxtext').css('opacity');
scrollPos = $(this).scrollTop();
if (scrollPos > pos) {
$('#boxtext').css({
'opacity': 1-(scrollPos/(100+pos))
});
} else{
$('#boxtext').css({
'opacity': 1-(1/(100+scrollPos))
});
}
//console.log(opa);
}
$(document).scroll(function() {
var pos = $('#box').position().top;
parallaxFade(pos);
});
.box{
width:200px;
height:200px;
background-color:red;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="ipsum">
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<div class="box" id="box">
<h3 class="boxtext" id="boxtext">Heading</h3>
</div>
<p>Lorem Ipsum Lorem IpsumLorem Ipsum</p>
<p>Lorem Ipsum Lorem IpsumLorem Ipsum</p>
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</div>