如何將一個JavaScript文件中的一個變量調用到另一個JavaScript文件中？

Question

目前，我有以下幾行代碼。 這是存儲在名為RealMapofIreland.js的JavaScript文件中的變量中的坐標數據。

var Real = [

        [53.286, -5.796], [53.140, -5.778], [52.525, -5.745], [52.152, -6.108], [51.756, -6.459], [51.481, -6.833], [50.987, -7.481], [50.812, -8.470],
        [50.361, -8.668], [50.097, -9.151], [50.217, -9.536], [48.373, -11.469], [48.10009, -11.85785], [49.1027, -13.27869], [49.38237, -14.06971],
        [51.50874, -16.36208], [51.86292, -15.74684], [52.1874, -15.74684], [52.42922, -18.5154], [55.02802, -19.26247], [55.14121, -21.12293],
        [55.5535, -21.59157], [56.897, -20.77103], [56.70451, -18.86696], [56.60789, -18.92206], [56.48676, -17.81227], [56.4382, -17.79416],
        [56.40782, -16.71381], [56.38198, -16.71111], [56.33481, -15.87885], [56.27996, -15.87705], [56.23114, -14.87909], [56.18225, -14.87729],
        [56.18225, -14.16318], [56.15167, -14.07529], [56.12412, -13.70725], [56.10575, -13.70315], [56.08277, -13.19273], [56.05517, -13.20921],
        [55.628, -7.42491], [55.6311, -7.28484], [55.61559, -7.26836], [55.62334, -7.13927], [55.61249, -7.13193], [55.61249, -6.92319],
        [55.33539, -6.77123]

];

在另一個名為LeafletMap.js的Javascript文件中，我嘗試從RealMapofIreland.js調用變量“ Real”

var polyline = L.polyline(
                  Real,
                  { color: 'red', weight: 2 }
               ).addTo(map);

然后在主頁中，我都調用了兩個JavaScript文件：

<script  src="js/RealMapofIreland.js"></script>
<script src="js/LeafletMap.js"></script>

這是行不通的。 我假設當在主頁中RealMapodIreland.js的Real ， RealMapodIreland.js將Real變量數據傳遞給LeafletMap.js折線函數。

我是否必須在另一個JavaScript文件中調用一個JavaScript文件，或者是否有更簡單的方法來執行此操作？

Answer 1

定義不帶var的變量。 如果使用var定義它，則該文件將成為該文件的私有文件，並且不是全局文件。

Real = [

        [53.286, -5.796], [53.140, -5.778], [52.525, -5.745], [52.152, -6.108], [51.756, -6.459], [51.481, -6.833], [50.987, -7.481], [50.812, -8.470],
        [50.361, -8.668], [50.097, -9.151], [50.217, -9.536], [48.373, -11.469], [48.10009, -11.85785], [49.1027, -13.27869], [49.38237, -14.06971],
        [51.50874, -16.36208], [51.86292, -15.74684], [52.1874, -15.74684], [52.42922, -18.5154], [55.02802, -19.26247], [55.14121, -21.12293],
        [55.5535, -21.59157], [56.897, -20.77103], [56.70451, -18.86696], [56.60789, -18.92206], [56.48676, -17.81227], [56.4382, -17.79416],
        [56.40782, -16.71381], [56.38198, -16.71111], [56.33481, -15.87885], [56.27996, -15.87705], [56.23114, -14.87909], [56.18225, -14.87729],
        [56.18225, -14.16318], [56.15167, -14.07529], [56.12412, -13.70725], [56.10575, -13.70315], [56.08277, -13.19273], [56.05517, -13.20921],
        [55.628, -7.42491], [55.6311, -7.28484], [55.61559, -7.26836], [55.62334, -7.13927], [55.61249, -7.13193], [55.61249, -6.92319],
        [55.33539, -6.77123]

];

Answer 2

如您的描述，這應該起作用。

在調用L.ployline函數之前，請檢查RealMapofIreland.js是否已加載。 要檢查Real變量是否已加載，請在L.ployline之前添加以下行：

console.log(Real);

然后打開瀏覽器的開發人員工具並重新加載頁面，您應該觀察到已記錄了Real值。 任何類似未定義變量的警告都應引起注意。

如果是這樣，但這也不起作用，請如下更改RealMapofIreland.js：

window.Real = [ ..... ];

和L.ployline函數類似：

var polyline = L.polyline(
                  window.Real,
                  { color: 'red', weight: 2 }
               ).addTo(map);

Answer 3

1. 首先，要確保文件以正確的順序加載，請使用“ defer”屬性。 <script defer src="js/RealMapofIreland.js"></script> <script defer src="js/LeafletMap.js"></script>

2. 嘗試為每個包含的文件創建窗口屬性數據。

    window.RealMap = {};window.RealMap.Real = [ [53.286, -5.796], [53.140, -5.778], [52.525, -5.745], [52.152, -6.108], [51.756, -6.459], [51.481, -6.833], [50.987, -7.481], [50.812, -8.470], [50.361, -8.668], [50.097, -9.151], [50.217, -9.536], [48.373, -11.469], [48.10009, -11.85785], [49.1027, -13.27869], [49.38237, -14.06971], [51.50874, -16.36208], [51.86292, -15.74684], [52.1874, -15.74684], [52.42922, -18.5154], [55.02802, -19.26247], [55.14121, -21.12293], [55.5535, -21.59157], [56.897, -20.77103], [56.70451, -18.86696], [56.60789, -18.92206], [56.48676, -17.81227], [56.4382, -17.79416], [56.40782, -16.71381], [56.38198, -16.71111], [56.33481, -15.87885], [56.27996, -15.87705], [56.23114, -14.87909], [56.18225, -14.87729], [56.18225, -14.16318], [56.15167, -14.07529], [56.12412, -13.70725], [56.10575, -13.70315], [56.08277, -13.19273], [56.05517, -13.20921], [55.628, -7.42491], [55.6311, -7.28484], [55.61559, -7.26836], [55.62334, -7.13927], [55.61249, -7.13193], [55.61249, -6.92319], [55.33539, -6.77123] ]; 

在“ LeafletMap.js”中

var polyline = L.polyline(
                  window.RealMap.Real,
                  { color: 'red', weight: 2 }
               ).addTo(map);