JSFiddle - React, Tailwind, and code Playground

HTML

<input type="file" id="file-upload"/>

JavaScript

var elmFileUpload = document.getElementById('file-upload');

function onFileUploadChange(e) {
	var file = e.target.files[0];
	var fr = new FileReader();
	fr.onload = onFileReaderLoad;
	fr.readAsDataURL(file);
}

function onFileReaderLoad(e) {
	var bgStyle = "url('" +e.target.result + "')";  
	elmFileUpload.parentElement.style.background = bgStyle;  
};

elmFileUpload.addEventListener('change',onFileUploadChange,false);