Reading a text file using Javascript
Question
The following code should read the content of a text file which is in the current directory upon load, and display it on the html page. I tried modifying by my self. But it does not give an output. Is there an easier way to get this result using another method? or please help figure out what is wrong with this code?
<html>
<head>
<meta http-equiv='Content-type' content='text/html;charset=UTF-8' >
<script>
function startRead()
{
// obtain input element through DOM
var file = document.getElementById("\\file.txt").files[0]
if(file)
{
getAsText(file);
}
}
function getAsText(readFile)
{
var reader;
try
{
reader = new FileReader();
}catch(e)
{
document.getElementById('output').innerHTML =
"Error: seems File API is not supported on your browser";
return;
}
// Read file into memory as UTF-8
reader.readAsText(readFile, "UTF-8");
// Handle progress, success, and errors
reader.onload = loaded;
reader.onerror = errorHandler;
}
function loaded(evt)
{
// Obtain the read file data
var fileString = evt.target.result;
document.getElementById('output').innerHTML = fileString;
}
function errorHandler(evt)
{
if(evt.target.error.code == evt.target.error.NOT_READABLE_ERR)
{
// The file could not be read
document.getElementById('output').innerHTML = "Error reading file..."
}
}
//Start reading file on load
window.addEventListener("load", startRead() { }, false);
</script>
</head>
<body>
<pre>
<code id="output">
</code>
</pre>
</body>
</html>
Given below is the code which I modified to get the above code. My intention was. As I open the html file it would read the text file which is in the current directory and display the content.
<html>
<head>
<meta http-equiv='Content-type' content='text/html;charset=UTF-8' >
<script>
function startRead()
{
// obtain input element through DOM
var file = document.getElementById("file").files[0];
if(file)
{
getAsText(file);
}
}
function getAsText(readFile)
{
var reader;
try
{
reader = new FileReader();
}catch(e)
{
document.getElementById('output').innerHTML =
"Error: seems File API is not supported on your browser";
return;
}
// Read file into memory as UTF-8
reader.readAsText(readFile, "UTF-8");
// Handle progress, success, and errors
reader.onload = loaded;
reader.onerror = errorHandler;
}
function loaded(evt)
{
// Obtain the read file data
var fileString = evt.target.result;
document.getElementById('output').innerHTML = fileString;
}
function errorHandler(evt)
{
if(evt.target.error.code == evt.target.error.NOT_READABLE_ERR)
{
// The file could not be read
document.getElementById('output').innerHTML = "Error reading file..."
}
}
</script>
</head>
<body>
<input id="file" type="file" multiple onchange="startRead()">
<pre>
<code id="output">
</code>
</pre>
</body>
</html>
3 answers
solution1
6 ACCPTED 2015-05-26 09:22:06
Try this snippet, I just tried and it works :)!
Live Demo (With Input File)
var fileInput = document.getElementById('fileInput'); var fileDisplayArea = document.getElementById('fileDisplayArea'); fileInput.addEventListener('change', function(e) { var file = fileInput.files[0]; var textType = /text.*/; if (file.type.match(textType)) { var reader = new FileReader(); reader.onload = function(e) { var content = reader.result; //Here the content has been read successfuly alert(content); } reader.readAsText(file); } else { fileDisplayArea.innerText = "File not supported!" } });
<input type="file" id="fileInput">
Without Input File
Function
function readTextFile(file){
var rawFile = new XMLHttpRequest();
rawFile.open("GET", file, false);
rawFile.onreadystatechange = function ()
{
if(rawFile.readyState === 4)
{
if(rawFile.status === 200 || rawFile.status == 0)
{
var allText = rawFile.responseText;
alert(allText);
}
}
}
rawFile.send(null);
}
And to test it
<a href="#" onclick="readTextFile("file:///C:/test.txt")"> Test </a>
Notice : I tried it, but it works only in firefox
solution2
1 2017-11-29 07:28:04
<html> <head></head> <body> <input type="file" id="openfile" /> <br> <pre id="filecontents"></pre> <script type="text/javascript"> document.getElementById("openfile").addEventListener('change', function() { var fr = new FileReader(); fr.onload = function() { document.getElementById("filecontents").textContent = this.result; } fr.readAsText(this.files[0]); }) </script> </body> </html>
this code works
<script type="text/javascript">
document.getElementById("openfile").addEventListener('change', function(){
var fr= new FileReader();
fr.onload= function(){
document.getElementById("readfile").textContent=this.result;
}
fr.readAsText(this.files[0]);
})
</script>
solution3
0 2017-08-22 10:27:42
<html>
<head>
<title>reading file</title>
</head>
<body>
var input = document.getElementById("myFile"); var output = document.getElementById("output"); input.addEventListener("change", function () { if (this.files && this.files[0]) { var myFile = this.files[0]; var reader = new FileReader(); reader.addEventListener('load', function (e) { output.textContent = e.target.result; }); reader.readAsBinaryString(myFile); } });
<input type="file" id="myFile"> <hr> <textarea style="width:500px;height: 400px" id="output"></textarea>
<input type="file" id="myFile">
<hr>
<!--<div style="width: 300px;height: 0px" id="output"></div>-->
<textarea style="width:500px;height: 400px" id="output"></textarea>
<script>
var input = document.getElementById("myFile");
var output = document.getElementById("output");
input.addEventListener("change", function () {
if (this.files && this.files[0]) {
var myFile = this.files[0];
var reader = new FileReader();
reader.addEventListener('load', function (e) {
output.textContent = e.target.result;
});
reader.readAsBinaryString(myFile);
}
});
</script>
</body>
</html>
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