如何使用javascript解析文本文件 [英] How can I parse a text file using javascript
问题描述
以下代码是使用javascript读取文本文件。有用。
但是,我只是想阅读部分内容。
例如,文件的内容是:Hello world!
我只想显示你好。
我试过函数 split(),但它只适用于字符串。我不知道如何在此处插入。
The code below is to read a text file using javascript. it works. However, I just want to read part of the content. For example, the content of the file is :"Hello world!" I just want to display "Hello". I tried function split(), but it only works on strings. I don't know how to insert it here.
var urls = ["data.txt"];
function loadUrl() {
var urlToLoad = urls[0];
alert("load URL ... " + urlToLoad);
browser.setAttributeNS(xlinkNS, "href", urlToLoad);
}
谢谢!!!
推荐答案
如果我正确理解了您的需要,请尝试阅读单独的单词。
创建一个内容为hello world的文件,并使用示例脚本浏览到该文件。
输出为你好。
Try this to read separate words if I understood correctly what you need. Create a file with the contents "hello world" and browse to it with the example script. The output is "hello".
<html>
<head>
<input type="file" id="fileinput" />
<script type="text/javascript">
function readSingleFile(evt) {
var f = evt.target.files[0];
if (f) {
var r = new FileReader();
r.onload = function(e) {
var contents = e.target.result;
var ct = r.result;
var words = ct.split(' ');
alert(words[0]);
}
r.readAsText(f);
} else {
alert("Failed to load file");
}
}
document.getElementById('fileinput').addEventListener('change', readSingleFile, false);
</script>
</head>
<body>
</body>
</html>
由于javascript对安全性的限制,直接读取必须使用ajax请求。
此代码shoudl执行请求的操作:
Reading directly has to be with an ajax request due to the javascript restrictions regarding safety. This code shoudl perform the requested operation:
<html>
<head>
<input type="file" id="fileinput" />
<script type="text/javascript">
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function(){
if(xmlhttp.status==200 && xmlhttp.readyState==4){
var words = xmlhttp.responseText.split(' ');
alert(words[0]);
}
}
xmlhttp.open("GET","FileName.txt",true);
xmlhttp.send();
</script>
</head>
<body>
</body>
</html>
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