How to open a local disk file with JavaScript?

Question

I tried to open file with

window.open(\"file:///D:/Hello.txt\");

The browser does not allow opening a local file this way, probably for sec

Answer 1

Because I have no life and I want those 4 reputation points so I can show my love to (upvote answers by) people who are actually good at coding I've shared my adaptation of Paolo Moretti's code. Just use openFile(function to be executed with file contents as first parameter).

function dispFile(contents) {
  document.getElementById('contents').innerHTML=contents
}
function clickElem(elem) {
	// Thx user1601638 on Stack Overflow (6/6/2018 - https://stackoverflow.com/questions/13405129/javascript-create-and-save-file )
	var eventMouse = document.createEvent("MouseEvents")
	eventMouse.initMouseEvent("click", true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null)
	elem.dispatchEvent(eventMouse)
}
function openFile(func) {
	readFile = function(e) {
		var file = e.target.files[0];
		if (!file) {
			return;
		}
		var reader = new FileReader();
		reader.onload = function(e) {
			var contents = e.target.result;
			fileInput.func(contents)
			document.body.removeChild(fileInput)
		}
		reader.readAsText(file)
	}
	fileInput = document.createElement("input")
	fileInput.type='file'
	fileInput.style.display='none'
	fileInput.onchange=readFile
	fileInput.func=func
	document.body.appendChild(fileInput)
	clickElem(fileInput)
}

Click the button then choose a file to see its contents displayed below.
Open a file