如何包含 JavaScript 个库？

Question

我在代码中包含 proj4.js JavaScript 库时遇到问题。代码如下所示：

<!DOCTYPE html>
<html>
<head>
    <title>Proj4js Testing</title>
</head>
<body onload="convertCoordinates()">
    <script type="text/javascript" src="proj4.js">
        function convertCoordinates() {
            var sourceProjection = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs";
            var targetProjection = "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs";
            proj4(sourceProjection, targetProjection, [15, 55]);
            alert("Done!");
        }
    </script>
</body>
</html>

但它从来没有给我一条消息说 "Done!"。我对 JavaScript 知之甚少，但看不到这段代码中的问题。我关注了 the user guide on GitHub.

Answer 1

它们需要分开 <script> 标签：

<script type="text/javascript" src="proj4.js"></script>
<script type="text/javascript" >
    function convertCoordinates() {
        var sourceProjection = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs";
        var targetProjection = "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs";
        proj4(sourceProjection, targetProjection, [15, 55]);
        alert("Done!");
    }
</script>

Answer 2

您不能将内联 JavaScript 代码与外部加载的脚本组合在一起。相反，只需将您的脚本分成两个单独的块：

<script type="text/javascript" src="proj4.js"></script>

<script type="text/javascript">
        function convertCoordinates() {
            var sourceProjection = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs";
            var targetProjection = "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs";
            proj4(sourceProjection, targetProjection, [15, 55]);
            alert("Done!");
        }
</script>

如何包含 JavaScript 个库？

How to include JavaScript libraries?

javascript

proj4js