javascript - 更改标题图像的地理位置检测器脚本

Question

我制作了一个相当大的脚本，它将使用浏览器地理定位功能检测用户所在的地理区域，然后更改背景图像并将其淡入到标题中。

现在它是一系列条件 if/else if 语句。效果很好，但只是代码开始看起来相当大。

<script type = "text/javascript" >

var geoHeader = document.getElementById("geozones");


function locate() {
    if (navigator.geolocation) {
        console.log('getting geolocation information...');
        navigator.geolocation.getCurrentPosition(function (position) {

            // Determine if in brisbane
            if (position.coords.latitude >= -27.936539 && position.coords.latitude <= -26.772950 && position.coords.longitude >= 152.439692 && position.coords.longitude <= 153.543818) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0004/315409/gelocation-selection-Enlisting-depot-in-Brisbane-during-World-War-I.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Brisbane');

                //Determine if in Barcaldine
            } else if (position.coords.latitude >= -23.741146 && position.coords.latitude <= -23.450440 && position.coords.longitude >= 145.117460 && position.coords.longitude <= 145.484472) {
                geoHeader.style.backgroundImage = 'url(http://i1167.photobucket.com/albums/q640/coolwebs/barcaldine-pub_zpsf8oazwr8.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Barcaldine');

                //Determine if in Beerburrum boundaries 
            } else if (position.coords.latitude >= -26.998834 && position.coords.latitude <= -26.892941 && position.coords.longitude >= 143.313919 && position.coords.longitude <= 153.01622) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0016/315421/gelocation-selection-View-of-Beerburrum-showing-the-hospital-building-on-the-hill-and-houses-in-the-street-ca-1921.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Beerburrum');

                //Determine if in Biggenden boundaries
            } else if (position.coords.latitude >= -25.743886 && position.coords.latitude <= -25.173518 && position.coords.longitude >= 151.750732 && position.coords.longitude <= 152.365966) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0017/315422/gelocation-selection-Woman-seated-in-a-Red-Cross-ambulance-Biggenden-19141918.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Biggenden');

                //Find out Charleville boundaries
            } else if (position.coords.latitude >= -26.735435 && position.coords.latitude <= -25.982371 && position.coords.longitude >= 145.503569 && position.coords.longitude <= 146.679106) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0004/315418/gelocation-selection-Red-Cross-workers-Charleville-1914.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                console.log('You might be in Barcaldine');

                //Determine if in Chinchilla boundaries
            } else if (position.coords.latitude >= -27.016575 && position.coords.latitude <= -26.504023 && position.coords.longitude >= 150.383621 && position.coords.longitude <= 150.913711) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0005/315419/gelocation-selection-Returned-soldiers-in-uniform-surrounding-the-Digger-War-Memorial-in-Chinchilla-ca.-1920.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Chinchilla');

                //Determine if in Cairns boundaries
            } else if (position.coords.latitude >= -17.216314 && position.coords.latitude <= -16.619826 && position.coords.longitude >= 145.477123 && position.coords.longitude <= 146.013393) {
                geoHeader.style.backgroundImage = 'url(http://i1167.photobucket.com/albums/q640/coolwebs/forms%20radio%20images/rex-lookout_zpsgnn4j1xx.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                console.log('You might be in Cairns');

                //Determine if in Lockyer Valley (Gatton and Helidon) boundaries
            } else if (position.coords.latitude >= -27.774956 && position.coords.latitude <= 27.422018 && position.coords.longitude >= 152.03981 && position.coords.longitude <= 152.495742) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0014/315410/gelocation-selection-Gatton-Mens-Auzzillary.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Lockyer Valley');

                //Determine if in Rockhampton
            } else if (position.coords.latitude >= -23.86413 && position.coords.latitude <= -22.348442 && position.coords.longitude >= 149.443603 && position.coords.longitude <= 150.783935) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0018/315414/gelocation-selection-March-to-Freedom-Column-at-Rockhampton-Queensland.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Rockhampton');

                //Determine if in Sunshine Coast (Buderim and Maleny) boundaries
            } else if (position.coords.latitude >= -26.862318 && position.coords.latitude <= -26.312145 && position.coords.longitude >= 152.807479 && position.coords.longitude <= 153.172775) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0020/315416/gelocation-selection-Parade-in-Maleny-ca.-1915.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Sunshine Coast');

                //Determine if in Thargomindah boundaries
            } else if (position.coords.latitude >= -28.378369 && position.coords.latitude <= -27.529237 && position.coords.longitude >= 143.313919 && position.coords.longitude <= 144.478469) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0015/315420/gelocation-selection-Selling-flowers-to-raise-funds-for-the-Red-Cross-Thargomindah-ca.-1916.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Thargomindah');

                //Determine if in Toogoolawah (in the Brisbane Valley) boundaries
            } else if (position.coords.latitude >= -27.402512 && position.coords.latitude <= -26.91376 && position.coords.longitude >= 152.210098 && position.coords.longitude <= 152.715469) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0003/315417/gelocation-selection-Peace-celebrations-in-Toogoolawah-1918.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Toogoolawah');

                //Determine if in Townsville boundaries
            } else if (position.coords.latitude >= -20.116181 && position.coords.latitude <= -18.363276 && position.coords.longitude >= 144.093261 && position.coords.longitude <= 147.619873) {
                geoHeader.style.backgroundImage = 'url(http://testing.slq.qld.gov.au/__data/assets/image/0019/315415/gelocation-selection-Members-of-the-Mens-Auxiliary-at-Townsville-Queensland.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('You might be in Townsville');

            } else {
                geoHeader.style.backgroundImage = 'url(http://i415.photobucket.com/albums/pp236/Keefers_/Keffers%20Animals/evilmonkey.jpg)';
                geoHeader.className = geoHeader.className + " fadeHeader";
                geoHeader.style.opacity = '1';
                console.log('We dunno where you are... evil monkey is watching you');
            }
        }, function () {
            geoHeader.style.opacity = '1';
            geoHeader.style.backgroundImage = 'url(http://i636.photobucket.com/albums/uu82/fireduptiger/Enchanted%20Forest/untitled.jpg)';
            geoHeader.className = geoHeader.className + " fadeHeader";
            geoHeader.style.opacity = '1';
            console.log('Too bad you are denying us your location. We are lost in the woods...');
        });
    } else {
        console.log('error message. Geolocation failed. Probably lacking browser support' + error.code);
    }
};

locate();

</script>

为了使脚本更小，我正在考虑通过循环脚本运行它并使用一系列数组来保存数据并循环遍历它。我只是担心在评估大量地理位置数据时它会变得有点棘手 - 其他一切都足够简单。

我很乐意在这里提出任何建议。

Answer 1

您可以将所有 header 存储在一个对象中，包括:

• 有坐标限制的区域
• 默认 - 如果位置已知，但不属于任何地区
• 禁用 - 如果位置未知，则禁用

像这样:

var headers = {
    regional : [
        {
            desc : "Brisbane",
            minLat : -27.936539,
            maxLat : -26.772950,
            minLong : 152.439692,
            maxLong : 153.543818,
            image : 'http://testing.slq.qld.gov.au/__data/assets/image/0004/315409/gelocation-selection-Enlisting-depot-in-Brisbane-during-World-War-I.jpg'
        }, {
            desc : "Barcaldine",
            minLat : -23.741146,
            maxLat : -23.450440,
            minLong : 145.117460,
            maxLong : 145.484472,
            image : 'http://i1167.photobucket.com/albums/q640/coolwebs/barcaldine-pub_zpsf8oazwr8.jpg'
        }
    ],
    def : 'http://testing.slq.qld.gov.au/__data/assets/image/0004/315409/gelocation-selection-Enlisting-depot-in-Brisbane-during-World-War-I.jpg',
    disabled : 'http://i636.photobucket.com/albums/uu82/fireduptiger/Enchanted%20Forest/untitled.jpg'
};

然后编写一个函数，遍历数组寻找特定区域，如果找不到则返回默认区域:

function getHeaderForCoordinates(lat, lng) {
    for (var i = 0; i < headers.regional.length; i++)
    {
        var header = headers.regional[i];

        if (lat >= header.minLat && lat <= header.maxLat 
         && lng >= header.minLong && lng <= header.maxLong) 
        {
            console.log("User is from " + header.desc);
            return header.image;
        }
    }

    console.log("User has geolocation, but region is unknown");
    return headers.def;
}

然后，您将能够以这种方式在代码中使用它:

function wrapWithUrl(url) { // just an utility function
    return "url('" + url + "')";
}

navigator.geolocation.getCurrentPosition(function (position) {
    var url = getHeaderForCoordinates(position.coords.latitude, position.coords.longitude);
    getHeader.style.backgroundImage = wrapWithUrl(url);
}, function () {
    geoHeader.style.backgroundImage = wrapWithUrl(headers.disabled);
});