JSFiddle - React, Tailwind, and code Playground

by Renilson Meneguci

HTML

<input type="file" name="anexo" id="idAnexo" data-max-size="5" />
                <input type="button" id="adicionarAnexo" value="Incluir anexo"/>

JavaScript

$(function () {
            $("#adicionarAnexo").click(function () {
                var fileInput = $('#idAnexo');
                var maxSize = $('#idAnexo').data('max-size');
                console.log(fileInput.get(0).files[0].size);

                //aqui a sua função normal
                if (fileInput.get(0).files.length) {
                    var fileSize = fileInput.get(0).files[0].size; // in bytes
                    if (fileSize > maxSize) {
                        alert('file size is more then' + maxSize + ' bytes');
                        return false;
                    } else {
                        alert('file size is correct- ' + fileSize + ' bytes');
                    }
                } else {
                    alert('choose file, please');
                    return false;
                }
            });
        });