Pro JavaScript for Web Apps pdf - EBook Free Download

CHAPTER 6 STORING DATA IN THE BROWSER $()($)Total:$In this listing, I use the JSON.stringify method to store a copy of the view model data when the Ajaxrequest is successful:$.getJSON("products.json", function(data) {cheeseModel.products = data;localStorage["jsondata"] = JSON.stringify(data);})I added the products.json URL to the NETWORK section of the manifest for this web app, so I have areasonable expectation that the data will be available and that the Ajax request will succeed.If, however, the request fails, which will definitely happen if the browser is offline, then I try tolocate and restore the serialized data from local storage, like this:}).error(function() {if (localStorage["jsondata"]) {cheeseModel.products = JSON.parse(localStorage["jsondata"]);}})Assuming the initial request works, I will have a good fallback position if subsequent requests fail.The effect that this technique creates is similar to the way that Firefox handles Ajax requests when thebrowser is offline because I end up using the last version of the data I was able to obtain from the server.152www.it-ebooks.info