I am (mostly) a front-end developer working on a prototype with a backend guy on a site. The basics of it would require a user login area, as well as a search form that would search and return results from a database table.
He is doing the backend logic with Java and PostgreSQL. He proposes to return a JSON format to me upon a query. This means I will have to take the data from the JSON string and populate/create the HTML markup. I can do this with either Javascript, or PHP. It seems to be that PHP would be a no brainer as I don't need to create HTML markup with Javascript/jQuery and also all the data populated by the server already, reducing the load on the client side, but this means as a "front-end" person I am also writing PHP.
And regarding loading all server data onto a page with Javascript, is this standard practice? Or should it only be used on AJAX?
Should the backend guy be generating the markup as well? What's the best way of separating this frontend and backend work? THanks!
If you are using PHP, you are a backend-guy, too.
If the markup is generated by the server, than you would usually not write an AJAX-application, because the markup is generated by the server.
In fact if you want to write a ajax-application, you have to manipulte the DOM with Javascript. Use jQuery or something like that to do this.
Seperating frontend and backend is done by creating an Interface, a contract which will separate the UI from the Backend-Logic. In your case the contract is the format of your JSON Data.
A good compromise would be to do either:
Option 1
A small PHP script server-side which formats the restults into a table with appropriate Ids/similar to allow javascript to add classes for styling. This entire table could be returned via an AJAX call and placed within a placeholder div on the page.
Option 2
The server returns simple JSON to the front-end, the front-end uses whatever mechanism it sees fit to build the appropriate HTML
The first one is a little cleaner to code - The generation of the HTML is seperated from the styling, but it's an extra hop (the PHP) and is slightly inflexible - the JS can modify the table as appropriate but it's limited by the html PHP sends.
The second is slightly more verbose to code but completely flexible.
I send the data from the server to the browser in JSON all the time, format on the browser with templates of one form or another. I would rather work with arrays in Javascript as the array methods like map and filter make it much easier.
Related
I just started writing server code (php), I finished the client side with javascript and html. I have some questions that I hope to get some clarification on before I start coding the server side.
Is it possible/a good idea to create DOM elements (img, p, header etc) on the server side (php), send it to the client side via AJAX, client side set some extra attribute and 'attach' it (the received DOM) to a div on that html page?
I want this because those DOM elements will be used on multiple pages.
Is it possible, and if possible, is sending the entire DOM efficient?
When sending raw HTML rather than JSON you want to consider things like:
the size of the request is going to be bigger. JSON is much more succinct
the time to render the element is going to be shorter (no need to parse the JSON and render the HTML, you're already done it server side)
reusability and caching is pretty easy. Indeed, The same snippet could be served to multiple clients and the template can be cached (the same is true if you used precompiled template in JS, but it's slightly more complex).
Code logic is all in one place (server side) or in two places (JS and server side).
The recommended way to accomplish what you want is using a Template Engine, which out there are plenty of them.
This way you can have separate files for the templates and load them as necessary via an AJAX request.
I recommend you the use of Handlebars, its pretty simple and you can use it with JavaScript and also with PHP itself!!!
See the PHP Handlebars port here: https://github.com/XaminProject/handlebars.php
I'm working on a editing tool (type of a simple CMS) in PHP/MySQL for a product catalog. I have search the Internet for a solution but I don't even know what to search for. So now my hope is on you guys.
I have a form where you can put all kinds of data like part.no, description an so on. All of this data is saved into a MySql table (items). I also have a table with predefined specifications.
What I want to do, and that I can't find a solution for, is to have a dropdown meny (or similar) and a add button to add a row for each related specifications without saving the whole form each time. I want to save first when all specifications is selected.
So, can I use PHP for this or do I need jQuery/Javascript or similar? I know it's possible, have seen it in OpenCart :-)
I hope someone understands my question. It's hard to explane i a language I'm not fully manage.
Regards
Client-side vs Server-side
Javascript: This sits in the user's browser. So anything you want to move in the user's browser will be done with JavaScript. This is "client-side"
PHP: This site on the server, so takes inpute from the user's browser and gives back a response (generally HTML, but can also be JSON or XML which is read by Javascript.). This is "server-side".
Libraries
jQuery: This is a set of functions written for Javascript to make it easier. So it runs in the user's browser and makes it easier for you to write bits that move on the screen.
You get similar libraries that help you write PHP (commonly called "frameworks") and there are many others for javascript as well.
Where to start
Write your HTML page as you want it to look. Keep it simple for the first time.
Then write some javascript (possibly using jQuery) to move the menu. Google "jquery menu dropdown" or similar and you'll find a solution you cna customise.
Then write some PHP that gives you the HTML you wrote in '1'.
Then decide what's going to happen when you click on a link in the HTML, and repeat the process (write HTML, incorporate Javascript to make it move, write PHP to give HTML)
Then work out which bits of the HTML are common or structured and should come from a database.
Without writing it for you (in which case you'll never learn) best to start one bit at a time and build as your knowledge grows. Bucket loads of examples on the web when youreach a particular problem you need to solve.
After comment "[how to] make it possible to select and add single/multiple specifications (from another table) without saving the whole form each time a specs is added":
Growing with AJAX
What you are asking is AJAX - this is where you get Javascript to talk to the server, and for javascript to move bits on the page based on the results. jQuery is probably the easiest (and probably has best documentation / examples for the ajax, as well as moving the DOM).
Basically: you have an "event" that you trap in JavaScript, example
/// Using jQuery to trap a button click
$().ready( function() {
$("#ButtonID").click( function(e) {
e.preventDefault();
alert('Button Clicked');
});
});
Then you build in an AJAX call inside that event (also check out get or post as the syntax is easier, you just get less control). The AJAX wil send a request to your PHP server, and you can get PHP to return HTML which you can replace/insert using the DOM manipulation functions linked below (e.g. before, html etc) or, when you get more advanced, you'll send back JSON which is a data structure you cna more easily manipulate in JavaScript to stipulate what actions are required.
As above, without actually writing it for you, the best place to start is to read the docs and have a go. Google "jquery AJAX PHP table example" or similar and you'll find an example somewhere.
I use a MVC PHP framework to keep my web applications as DRY as possible. All of my HTML templates are neatly tucked away in one folder in the application scope of my project.
The problem is that whenever I use a JSON string to build a page with AJAX, I need to reuse a lot of lines from these templates and copy them somewhere in my JavaScript files. This means there is code duplication between templates in my JavaScript files and templates in my PHP application.
I was wondering how this duplication can be prevented. One way is of course to load the template using AJAX, but then I would end up with a double AJAX request for one page. Furthermore, the PHP templates uses different tag styles to represent variables than MooTools, but the HTML setup is the same.
So to summarize: is there any neat way or a tool to prevent duplication of templates so one file could be used in both PHP and JavaScript? For the record: I use the MooTools framework to build my JavaScript files.
Edit
After some research, I found the best answer yet in my opinion. For those who are interested:
PURE
PURE separates HTML representation and JavaScript logic completely so you don't have to bother including HTML elements in your scripts. The template can simply be provided in the HTML file itself.
Example:
// JSON string
{ 'who': 'me' }
// In your rendered HTML page:
<div id="who"></div>
// After the JSON string is sent back
<div id="who">me</div>
Furthermore, it can be used by a wide selection of libraries: MooTools, jQuery, dojo, Prototype etc.
Interesting question that I'm struggling with sometimes too.
you can put your html in your javascript code, which is duplicating and which you want to avoid
you can load your html with a separate ajax call, which causes more ajax calls to be run, and possible slowing down of your app. you may want to avoid it.
you can pass your html within the Ajax call that will load the data. That way, you only have one call. Let your PHP open your templates, and add them to the data-json stream.
you can put the template inside your original html, put it as hidden.
I'd go for solution 3, or possibly 4 if templates are small and limited.
The JSon would then be something like {"data": ... your original data object, "templates":{...}}
You might be looking for a template langugage that is available for multiple languages so you can re-use your templates across language boundaries.
One such template language is {{mustache}}, works in both PHP and Javascript and many more languages.
What's a better practice? Load data in HTMLformat or JSON-format? When I load HTML i'm able to keep all the html in my php view-file. When i load JSON I have to put it in html elements clientside with javascript.
I know that a 'best-practice-question' isn't suitable for stackoverflow. So a better answer to my question is a list of benefits and disadvantages of both techniques.
I'd say use JSON whenever you need to process the data client-side, use HTML when you just want to dump it into some container-div.
For example, consider an image viewer, you can fetch a list of preview-image-urls using JSON, create a list of images client side and display them, scroll them around and so on.
On the other hand, if you're performing some action using ajax, and you just want to display a status message (like your table of data in the popup div), I'd suggest rendering the HTML on server side and just display it.
If you plan to call the data often in the same session, the network traffic and the responsiveness will be better if you just call JSON data. The HTML/JS overhead being in the cache, only data will cross the network from the second call.
However it looks you just need to render a table with TRs/TDs. If you don't call it often, you're better off with a simple HTML dump.
Another consideration is about clearly separating the data and the view, for cleaner code and easier maintenance. A JSON call allows a clear separation between data and HTML. In an HTML dump both are mixed.
I've just answered to another question, it was for JSP, but that may interest you.
What is the best approach for handling a complex form in html?
If you later have to do a mobile version, or another client in general, you might benefit from using JSON all over. JSON will also be smaller (might matter or not, depending on your html, the amounts of elements, ...)
Here's a good article on the subject: http://www.quirksmode.org/blog/archives/2005/12/the_ajax_respon.html
I've been asked to create a web UI that allows a user to modify a specific section of the HTML DOM and then POST the modifications back to the server for storage. The modification should be done via drag'n'drop, with my tool of choice being jQuery. The server will be PHP, but written by someone else since I'm not a PHP programmer.
The only way I can think to do this is to send back to the server the entire DOM section via AJAX whenever it is modified. However, that is expensive since the section could be quite large. Furthermore I'm not sure how I'd efficiently capture the modified section and write it to a string which can be sent to the server. Overlapping events would also be a big concern.
Any ideas for a better approach? Are there libraries/tools (JavaScript or server-side) that I should be considering? Many thanks.
Well if you are dealing with some list of elements, say rows in table you can send back a map where particular row is mapped to a position then when you re-initialize the page you can feed such map back and rearrange the list.
Also - another idea (since you are using PHP) you can have some sort of a model on the back end which backs your visual DOM element, then again - you send back some parameters you have changed (order, size, etc.) and adjust/save the model
Instead of sending the entire DOM section you should try to serialize the DOM section you're sending to something more lightweight (like JSON). Since it's HTML, serializing it to JSON will dramatically reduce it's size.
Apart from that I think there's not much you can do besides some AJAX request to allow the server to save the changes.
You'd want to use something like the UI plugin to facilitate the actual dragging/dropping/reorganizing. I don't know of any libraries that will pick out DOM objects and AJAX information to a server in a particular fashion, so you would probably have to code something like that yourself to suit your specific needs. It might help to know what sort of DOM node you're trying to send.
If you're building something like a custom WYSIWYG, sending the entire node might be the best approach without losing information. If you're doing something simple like allowing users to drag and drop to reorder a list something like the following code might suffice:
var toPost = '';
function handler(data) {//handle server response}
$("ul#container li").each(function(){toPost+=this.getAttribute('rel');});
$.post('processing_script.php',{data:toPost},handler);
I checked into how Google handles these. If you drag and drop an element on the iGoogle homepage, a GET request is sent to the Google handling script with the following parameters:
et '4af26272PQUMZP8V'
mp '19_1:4_1:7_1:13_1:16_1:18_2:2_2:3_2:14_2:11_2:_opt_3:17_3:6_3:12_3'