33 lines
1.1 KiB
JavaScript
33 lines
1.1 KiB
JavaScript
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//如果需要头部导航栏固定，把下面代码全部删除即可。
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var new_scroll_position = 0;
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var last_scroll_position;
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var byg_header_nav = document.getElementById("byg_header");
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var header_scroll_d = 0, header_scroll_t = 0;
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window.addEventListener('scroll', function(e) {
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last_scroll_position = window.pageYOffset;
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if (last_scroll_position > 150 && last_scroll_position < (document.documentElement.scrollHeight - window.innerHeight - 20)) {
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// 向下滚动
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if (new_scroll_position < last_scroll_position) {
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header_scroll_d = last_scroll_position;
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if (header_scroll_d > header_scroll_t + 50) {
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byg_header_nav.classList.remove("slideDown");
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byg_header_nav.classList.add("slideUp");
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}
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// 向上滚动
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} else if (new_scroll_position > last_scroll_position) {
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header_scroll_t = last_scroll_position;
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if (header_scroll_d > header_scroll_t + 50) {
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byg_header_nav.classList.remove("slideUp");
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byg_header_nav.classList.add("slideDown");
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}
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}
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new_scroll_position = last_scroll_position;
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} else {
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byg_header_nav.classList.remove("slideUp");
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byg_header_nav.classList.add("slideDown");
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}
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});
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