HTML & JScript – Read and Encode file
We got a requirement in ADX portal, to read and convert the file content to Base64String , which eventually will be submitted to an external API.
Below is the code snippet to read the File content, browsed using the HTML ‘File Upload’ control:
function readFileAsText(){
try {
// Read the browsed file from ‘File Upload’ control.
var fileToLoad = document.getElementById(“fileOE“).files[0];var fileReader = new FileReader();
fileReader.onload = function (fileLoadedEvent) {
// Set the file content to variable
var textFromFileLoaded = fileLoadedEvent.target.result;
alert(“File Content – ” + textFromFileLoaded);// Using ‘window.btoa’ encode the plain text to Base 64
var convertedString = window.btoa(unescape(encodeURIComponent(textFromFileLoaded)));
alert(“Base 64 content – ” + convertedString);
};fileReader.readAsText(fileToLoad, “UTF-8”);
} catch (e) {
alert(“Error in readFileAsText(); Error – ” + e.description);
}
}<body>
<label for=”fileOE”>Pick the file </label><br>
<input type=”file” id=”fileOE” />
<input type=”button” value=”Upload” onclick=”readFileAsText()” />
</body>
- Execute the code and you will get output as below
File content as text
Encoded File Content (Base 64)
🙂
Rajeev Pentyala - Microsoft Power Platform 