The principle and implementation of jquery's lazy loading

This time I will bring you the principle and implementation of jquery's lazy loading. What are the things to note when implementing jquery's lazy loading? The following is a practical case, let's take a look.

The principle of lazy loading

1. Code implementation, load into the current viewport:

function isVisible($node){    var winH = $(window).height(),
        scrollTop = $(window).scrollTop(),
        offSetTop = $(window).offSet().top;    if (offSetTop < winH + scrollTop) {        return true;
    } else {        return false;
    }
}

2. Then add the browser's

eventlistening Function, let the browser check whether the element appears within the visible range of the window every time it scrolls:

$(window).on("scroll", function{    if (isVisible($node)){        console.log(true);
    }
})

3. Come on, Pikachu!

var hasShowed = false;
$(window).on("sroll",function{    if (hasShowed) {        return;
    } else {        if (isVisible($node)) {
            hasShowed = !hasShowed;            console.log(true);            //ajax请求刷新view层
        }
    }
})

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to the php Chinese website

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