我设置了一个jQuery函数,当某个div进入视图时会改变body的背景颜色,例如,当#block-three
(其中包含黑色文本)出现时,body的背景颜色会变为白色,并在这个div离开视图时恢复原来的颜色。这个功能很好用,但是变化非常突然,我正在寻找一种更平滑的背景颜色过渡方式,即在滚动时进行颜色渐变(如果可能的话)。
jsFiddle演示:http://jsfiddle.net/neal_fletcher/TB53d/
HTML:
<div id="block-one" class="block">
<div class="inner-block">Test</div>
<div class="inner-block"></div>
<div class="inner-block"></div>
</div>
<div id="block-two" class="block">
<div class="inner-block">Test</div>
</div>
<div id="block-three" class="block">
<div class="inner-block">Test</div>
<div class="inner-block"></div>
</div>
<div id="block-four" class="block">
<div class="inner-block">Test</div>
<div class="inner-block"></div>
<div class="inner-block"></div>
</div>
<div id="block-five" class="block">
<div class="inner-block">Test</div>
<div class="inner-block"></div>
<div class="inner-block"></div>
</div>
jQuery:
var blockHeight = [];
$(".block").each(function () {
blockHeight.push($(this).height());
});
function hoverCurrentItem() {
var sIndex = 0;
var totalHeight = 0;
var scrolled = $(window).scrollTop();
for (var i in blockHeight) {
totalHeight += blockHeight[i];
if (totalHeight > scrolled) {
break;
} else {
sIndex++;
}
}
var $sItem = $(".block").eq(sIndex);
if (!$sItem.hasClass("selected")) {
$(".selected").removeClass("selected");
$sItem.addClass("selected");
}
if ($("#block-three").hasClass("selected")) {
$("body").css("background-color", "white");
} else {
$("body").css("background-color", "black");
}
}
hoverCurrentItem();
$(window).scroll(function (e) {
hoverCurrentItem()
});
任何建议将不胜感激!