Without jQuery:
const $output = document.getElementById('output')
document.getElementById('file').onchange = function() {
var file = this.files[0];
var reader = new FileReader();
reader.onload = function(progressEvent) {
// Entire file
const text = this.result;
$output.innerText = text
// By lines
var lines = text.split('\n');
for (var line = 0; line < lines.length; line++) {
console.log(lines[line]);
}
};
reader.readAsText(file);
};
<input type="file" name="file" id="file">
<div id='output'>
...
</div>
Remember to put your javascript code after the file field is rendered.