[英]How to stick div on top of the page
我只想將div放在頁面頂部
如果有人滾動頁面,則綠色div stickdiv
應該自動stickdiv
在頂部
var left = document.getElementsByClassName("stickdiv");
for( var i = 0;i<left.length;i++){
var stop = (left[0].offsetTop);
window.onscroll = function (e) {
var scrollTop = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;
if (scrollTop >= stop) {
left.className += " stick"; //adding a class name
} else {
className = '';
}
}
}
為什么在div上添加Stick類不起作用-https: //jsfiddle.net/kzk5qab2/1/
我只想將div像黃色的div一樣放在頂部-http: //jsfiddle.net/qc4NR/
您已經遍歷了left
項的數組,但是在嘗試將類名稱添加到元素時忘記了引用數組索引。
var left = document.getElementsByClassName("stickdiv"); for (var i = 0; i < left.length; i++) { var stop = (left[0].offsetTop); window.onscroll = function(e) { var scrollTop = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop; // left.offsetTop; if (scrollTop >= stop) { // get array item by index left[0].classList.add('stick'); //adding a class name } else { // get array item by index left[0].classList.remove('stick'); } } }
.stickdiv { height: 50vh!important; width: 100vh!important; background-color: green!important; } .stick { position: fixed; top: 0; margin: 0 0 } #right { float: right; width: 100px; height: 1000px; background: red; } .des { height: 300px; width: 100%; background-color: #000; }
<div class="des"></div> <div class="stickdiv"></div> <div id="right"></div>
如果直接選擇項目,甚至不需要循環,如下所示:
var left = document.querySelector(".stickdiv");
var stop = (left.offsetTop);
window.onscroll = function(e) {
var scrollTop = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;
// left.offsetTop;
if (scrollTop >= stop) {
left.classList.add('stick'); //adding a class name
} else {
left.classList.remove('stick');
}
}
根據您需要支持的瀏覽器,您不一定需要使用JS。
.sticky {
position: sticky;
left: 0;
top: 0;
width: 100%;
}
Codepen: https ://codepen.io/afisher88/pen/xJaxoP
瀏覽器對位置粘性的支持: https : //caniuse.com/#search=position%3A%20sticky
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