JQuery：如何在jquery選擇器中使用for循環變量？

Question

這是我的第一篇文章。

我正在嘗試制作一個照相館，但下面的代碼可用於我的網站。 我希望當在.preview類中懸停相同的nth-child時，同一nth-child在.gallery中受到影響。

$(document).ready(function() {
    $(".preview > :nth-child(1)").mouseover(function() {
        $(".gallery > :nth-child(1)").css("opacity","1");
        $(".gallery :not( > :nth-child(1))").css("opacity","0");
    });
    $(".preview > :nth-child(2)").mouseover(function() {
        $(".gallery > :nth-child(2)").css("opacity","1");
        $(".gallery :not( > :nth-child(2))").css("opacity","0");
    });
    $(".preview > :nth-child(3)").mouseover(function() {
        $(".gallery > :nth-child(3)").css("opacity","1");
        $(".gallery :not( > :nth-child(3))").css("opacity","0");
    });
    $(".preview > :nth-child(4)").mouseover(function() {
        $(".gallery > :nth-child(4)").css("opacity","1");
        $(".gallery :not( > :nth-child(4))").css("opacity","0");
    });
});

然后，我想到了一種使用for循環的更簡單方法。 稍后我計划將更多孩子添加到.gallery和.preview中，因此for循環將使代碼更簡單。 我認為在下面的代碼中問題出在for循環變量i中。 您能否看下面的代碼，看看我在做什么錯？

$(document).ready(function() {
    for (i = 1; i < preview.length; i++) {
        var selector1 = ".preview > :nth-child(" + i + ")";
        var selector2 = ".gallery > :nth-child(" + i + ")";
        var selector3 = ".gallery :not( > :nth-child((" + i + "))";
        $(selector1).mouseover(function() {
            $(selector2).css("opacity","1");
            $(selector3).css("opacity","0");
        });
    }
});

編輯：這是適用於的HTML：

<div class="gallery">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div class="preview">
            <div></div>
            <div></div>
            <div></div>
            <div></div>
        </div>
    </div>

編輯：這是CSS

.gallery > :nth-child(1) {
    background-image: url('https://sp.yimg.com/ib/th?id=HN.607997559404560656&pid=15.1&P=0');
    height: 500px;
    background-size: cover;
    opacity: 1;
}
.gallery > :nth-child(2) {
    background-image: url('http://www.kamionek.waw.pl/images/stories/2012/stadion_narodowy_ii_2012_kamionek_0001.jpg');
    height: 500px;
    background-size: cover;
    position: relative;
    top: -500px;
    opacity: 0;
    margin-bottom: -500px;
}
.gallery > :nth-child(3) {
    background-image: url('http://www.twojezaglebie.pl/wp-content/uploads/2012/02/stadion-narodowy-luty-2012_6521.jpg');
    height: 500px;
    background-size: cover;
    position: relative;
    top: -500px;
    opacity: 0;
    margin-bottom: -500px;
}
.gallery > :nth-child(4) {
    background-image: url('http://upload.wikimedia.org/wikipedia/commons/a/ac/Stadion_Narodowy_w_Warszawie_20120422.jpg');
    height: 500px;
    background-size: cover;
    position: relative;
    top: -500px;
    opacity: 0;
    margin-bottom: -500px;
}
.preview {
    height: 100px;
    width: 100px;
    width: 100%;
}
.preview div {
    height: 100px;
    width: 100px;
    background-size: cover;
    display: inline;
    float: left;
}
.preview > :nth-child(1) {
    background-image: url('https://sp.yimg.com/ib/th?id=HN.607997559404560656&pid=15.1&P=0');
}
.preview > :nth-child(2) {
    background-image: url('http://www.kamionek.waw.pl/images/stories/2012/stadion_narodowy_ii_2012_kamionek_0001.jpg');
}
.preview > :nth-child(3) {
    background-image: url('http://www.twojezaglebie.pl/wp-content/uploads/2012/02/stadion-narodowy-luty-2012_6521.jpg');
}
.preview > :nth-child(4) {
    background-image: url('http://upload.wikimedia.org/wikipedia/commons/a/ac/Stadion_Narodowy_w_Warszawie_20120422.jpg');
}

Answer 1

您可以使用現有的系統來執行此操作，例如： http : //jsfiddle.net/TrueBlueAussie/wn3c84ke/5/

$(document).ready(function () {
    $(".preview div").mouseover(function () {
        var $previews = $('.preview div');
        var $children = $(".gallery").children().not('.preview');
        var $selected = $children.eq($previews.index(this));
        $children.not($selected).css("opacity", "0");
        $selected.css("opacity", "1");
    });
});

它使用懸停的索引位置作為選擇索引，但實際上我會推薦這樣的數據驅動方法： http : //jsfiddle.net/TrueBlueAussie/wn3c84ke/7/

HTML：

<div class="gallery">
    <div id="one"></div>
    <div id="two"></div>
    <div id="three"></div>
    <div id="four"></div>
    <div class="preview">
        <div data-target="#one"></div>
        <div data-target="#two"></div>
        <div data-target="#three"></div>
        <div data-target="#four"></div>
    </div>
</div>

jQuery的

$(document).ready(function () {
    $(".preview > div").mouseover(function () {
        var $children = $(".gallery >  *:not(.preview)");
        var $selected = $($(this).attr("data-target"));
        $children.not($selected).css("opacity", "0");
        $selected.css("opacity", "1");
    });
});

Answer 2

一種使用循環的方法是：

$(document).ready(function() {
    $(".preview div").each(function(index,object){
        $(object).mouseover(function() {
            $(".gallery div").css("opacity","0");
            $(".gallery div")[index].css("opacity","1");
        });
    });
});

Answer 3

嘗試這個：

$(".preview").on("mouseover", function () {
    $(".gallery").children().index(this).css("opacity", "0");
    $(this).children().css("opacity", "1");
});