Function isElementInViewport

Zhihu-Enhanced.user.js:432–440

(el)

//获取元素是否在可视区域（完全可见）
function isElementInViewport(el) {
    let rect = el.getBoundingClientRect();
    return (
        rect.top >= 0 &&
        rect.left >= 0 &&
        rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
        rect.right <= (window.innerWidth || document.documentElement.clientWidth)
    );
}
//获取元素是否在可视区域（部分可见）
function isElementInViewport_(el) {
    let rect = el.getBoundingClientRect();