Gulp + BrowserSync (minimal config)

gulpfile.js

// Usage:
// $ npm install gulp browser-sync --save-dev
// $ gulp serve

'use strict';

var gulp = require('gulp');
var browserSync = require('browser-sync').create();

gulp.task('serve', function() {
    browserSync.init({
        server: {
            baseDir: "./"
        }
    });

    gulp.watch('./**/*.*').on('change', browserSync.reload);
});