11

我有一个 javascript/HTML5 页面，我想用它来拉入一个文件并检查每一行以查看它是否大于 240 个字符：

编辑：我现在可以正确解析东西，但它们没有正确呈现。这是我更新的代码：

<!DOCTYPE HTML>

<html>

    <head>

        <link href="https://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.1/css/bootstrap-combined.min.css" rel="stylesheet">
        <link href="https://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.1/css/bootstrap-combined.min.css" rel="stylesheet">

    </head>
    <body>

    <input type="file" id="input" name="file" multiple />
    <br>
    <output id="files"></output>

        <script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>

        <script>

            if (window.File && window.FileReader && window.FileList && window.Blob) {
                // Great success! All the File APIs are supported.
            } else {
                alert('The File APIs are not fully supported in this browser.');
            }


            function handleFileSelect(evt) {
                var files = evt.target.files; // FileList object


                // files is a FileList of File objects. List some properties.
                var output = [];
                for (var i = 0, f; f = files[i]; i++) {

                    var reader = new FileReader();

                    reader.onload = function(e) {
                            // Print the contents of the file
                            var text = e.target.result;

                            var lines = text.split(/[\r\n]+/g); // tolerate both Windows and Unix linebreaks

                            for(var i = 0; i < lines.length; i++) {
                                if (lines[i].length > 240){
                                    output.push('<li>' + lines[i] + '<br>');
                                }
                            }
                    };

                    reader.readAsText(f,"UTF-8");

                }
                document.getElementById('files').innerHTML = 'Paths with more than 240 characters: <br><ul>' + output.join('') + '</ul>';
            }

            document.getElementById('input').addEventListener('change', handleFileSelect, false);


        </script>
    </body>
</html>

我可以运行跟踪并查看output变量是否正确填充，但我得到的输出只是：Paths with more than 240 characters:没有output.join()正确渲染部分 - 有什么想法吗？

4

2 回答 2

9

显而易见的方法（如果您可以容忍一次全部读取文件）是用换行符分割它。

var lines = text.split(/[\r\n]+/g); // tolerate both Windows and Unix linebreaks
for(var i = 0; i < lines.length; i++) { /* do something with lines[i] */ }
// or in modern JavaScript,
lines.forEach(function(line) { /* ... */ });
于 2013-03-08T05:52:15.967 回答
3

我想你应该把

document.getElementById('files').innerHTML = 'Paths with more than 240 characters: <br><ul>' + output.join('') + '</ul>';

内部onload回调。当您尝试使用它时，似乎output尚未填充。所以：

reader.onload = function (e) {
    // all your code ...

    // now can safely print output
    document.getElementById('files').innerHTML = 'Paths with more than 240 characters: <br><ul>' + output.join('') + '</ul>';
};
于 2013-03-08T06:20:14.027 回答