アップロードしたファイルの内容をHTMLで表示したいのですが、テキストファイルをアップロードするだけです。私のexample.html:
<html xmlns="http://www.w3.org/1999/xhtml" >
<p>
Please specify a file, or a set of files:<br>
<input type="file" name="datafile" size="40">
</p>
<textarea id="2" name="y" style="width:400px;height:150px;"></textarea>
</html>
私はグーグルからここに来ましたが、実例がないことに驚きました。
const reader = new FileReader()
reader.onload = event => console.log(event.target.result) // desired file content
reader.onerror = error => reject(error)
reader.readAsText(file) // you could also read images and other binaries
以下の完全に機能する例を参照してください。
document.getElementById('input-file')
.addEventListener('change', getFile)
function getFile(event) {
const input = event.target
if ('files' in input && input.files.length > 0) {
placeFileContent(
document.getElementById('content-target'),
input.files[0])
}
}
function placeFileContent(target, file) {
readFileContent(file).then(content => {
target.value = content
}).catch(error => console.log(error))
}
function readFileContent(file) {
const reader = new FileReader()
return new Promise((resolve, reject) => {
reader.onload = event => resolve(event.target.result)
reader.onerror = error => reject(error)
reader.readAsText(file)
})
}
label {
cursor: pointer;
}
textarea {
width: 400px;
height: 150px;
}
<div>
<label for="input-file">Specify a file:</label><br>
<input type="file" id="input-file">
</div>
<textarea id="content-target"></textarea>
1つの方法を次に示します。
[〜#〜] html [〜#〜]
<tr>
<td>Select a File to Load:</td>
<td><input type="file" id="fileToLoad"></td>
<td><button onclick="loadFileAsText()">Load Selected File</button><td>
</tr>
JavaScript
function loadFileAsText(){
var fileToLoad = document.getElementById("fileToLoad").files[0];
var fileReader = new FileReader();
fileReader.onload = function(fileLoadedEvent){
var textFromFileLoaded = fileLoadedEvent.target.result;
document.getElementById("inputTextToSave").value = textFromFileLoaded;
};
fileReader.readAsText(fileToLoad, "UTF-8");
}
document.getElementById('input-file')
.addEventListener('change', getFile)
function getFile(event) {
const input = event.target
if ('files' in input && input.files.length > 0) {
placeFileContent(
document.getElementById('content-target'),
input.files[0])
}
}
function placeFileContent(target, file) {
readFileContent(file).then(content => {
target.value = content
}).catch(error => console.log(error))
}
function readFileContent(file) {
const reader = new FileReader()
return new Promise((resolve, reject) => {
reader.onload = event => resolve(event.target.result)
reader.onerror = error => reject(error)
reader.readAsText(file)
})
}
label {
cursor: pointer;
}
textarea {
width: 400px;
height: 150px;
}
<div>
<label for="input-file">Specify a file:</label><br>
<input type="file" id="input-file">
</div>
<textarea id="content-target"></textarea>
これを試して。
[〜#〜] html [〜#〜]
<p>
Please specify a file, or a set of files:<br>
<input type="file" id="myFile" multiple size="50" onchange="myFunction()">
</p>
<textarea id="demo" style="width:400px;height:150px;"></textarea>
[〜#〜] js [〜#〜]
function myFunction(){
var x = document.getElementById("myFile");
var txt = "";
if ('files' in x) {
if (x.files.length == 0) {
txt = "Select one or more files.";
} else {
for (var i = 0; i < x.files.length; i++) {
txt += (i+1) + ". file";
var file = x.files[i];
if ('name' in file) {
txt += "name: " + file.name + "";
}
if ('size' in file) {
txt += "size: " + file.size + " bytes ";
}
}
}
}
else {
if (x.value == "") {
txt += "Select one or more files.";
} else {
txt += "The files property is not supported by your browser!";
txt += "The path of the selected file: " + x.value; // If the browser does not support the files property, it will return the path of the selected file instead.
}
}
document.getElementById("demo").innerHTML = txt;
}
デモ (