Basic gulp watch file

commandline

$ npm install -g gulp
$ npm install browser-sync gulp --save-dev

gulpfile.js

var gulp = require("gulp");
var browserSync = require("browser-sync");

gulp.task("browser-sync", function() {
    browserSync({
        proxy: "http://localhost:8080"
    });
});

gulp.task("watch", ["browser-sync"], function () {
    gulp.watch(["*.html","*.css"]).on("change", browserSync.reload);
});