We Keep Coding

dynamically generate content for a page when clicking on product

everyone. I am making a website with t-shirts. I dynamically generate preview cards for products using a JSON file but I also need to generate content for an HTML file when clicking on the card. So, when I click on it, a new HTML page opens like product.html?product_id=id. I do not understand how to check for id or this part ?prodcut_id=id, and based on id it generates content for the page. Can anyone please link some guides or good solutions, I don't understand anything :(.

It sounds like you want the user's browser to ask the server to load a particular page based on the value of a variable called product_id.
The way a browser talks to a server is an HTTP Request, about which you can learn all the basics on javascipt.info and/or MDN.
The ?product_id=id is called the 'query' part of the URL, about which you can learn more on MDN and Wikipedia.
A request that gets a page with this kind of URL from the server is usually a GET request, which is simpler and requires less security than the more common and versatile POST request type.
You may notice some of the resources talking about AJAX requests (which are used to update part of the current page without reloading the whole thing), but you won't need to worry about this since you're just trying to have the browser navigate to a new page.
Your server needs to have some code to handle any such requests, basically saying:
"If anybody sends an HTTP GET request here, look at the value of the product_id variable and compare it to my available HTML files. If there's a match, send a response with the matching file, and if there's no match, send a page that says 'Error 404'."
That's the quick overview anyway. The resources will tell you much more about the details.

There are some solutions, how you can get the parameters from the url:
Get ID from URL with jQuery
It would also makes sense to understand what is a REST Api and how to build a own one, because i think you dont have a backend at the moment.
Here some refs:
https://www.conceptatech.com/blog/difference-front-end-back-end-development
https://www.tutorialspoint.com/nodejs/nodejs_restful_api.htm

Cross Domain AJAX query

With the help of Stack overflow I currently have this JSFiddle: http://jsfiddle.net/WskJT/
I have an aspx file on another server (cannot access this, so amendments to that server are not an option) and offline (php include not an option) I would have a page that pulls this data & removes columns as per the above fiddle.
Is there any workaround to be able to get this data from the aspx file & display (something similar to) the output the the above fiddle?
I'm an enthusiastic novice so I apologise if I haven't worded this correctly etc.
Thanks in advance!

Despite the server being on your intranet as you have indicated in your comments you will face security issues as pointed out. What you could do is create a 'proxy' web service in the same domain as your main page.
Start by creating a 'service.php' file on your own server. From there, make the necessary curl calls to the ASPX page on the other server. Any time service.php (or call it proxy.php if you like) is called, it in turn calls the ASPX page, with any parameters as required. Have it read the output text and return the text to the caller itself.
Point your AJAX code to the 'service.php' file.
Now your javascript calls are in the same domain and you shouldn't have the permission problems you were facing with the JavaScript.

MVC3, switching between Views in the same page

I am working on a MVC project that is supposed to have one page only, with two zones. On one zone I have a Google Map with markers, and the second zone is populated with the selected marker's details.
The details view has a button that when clicked should change the entire view into edit mode without refreshing the page or redirecting it. I have used two views, for details and edit and with the help of ajaxForm function I am switching back and forth between these two views. I'm adding the ajaxForm on documentready for edit view.
<script type="text/javascript">
// wait for the DOM to be loaded
$(document).ready(function() {
// bind 'myForm' and provide a simple callback function
$('#currentDiv').ajaxForm(function(data) {
$('#currentDiv').html(data);
});
});
</script>
The problem appears when on server-side an error appears while trying to save data from edit view and I want to return to the same edit view with the errors displayed. The ajaxForm handler is not added any more and even if the new values that will try to be saved are ok, the detail view is loaded in another page.
Unfortunately, the use of ajaxForm creates some other problems because I don't have control over the cases when the ajax call fails.
Any ideas on how could I fix this? Is it some other solution to switch between those two views without using ajaxForm and without refreshing the page?

I think there are a couple of different questions that you are asking.
First off, you add jquery handlers to deal with the case when you get a 500 type error from the server.
Something like the following. I suggest taking a look at the docs for more info.
$(document).ajaxError(function(event,jqXHR,ajaxSettings,thrownError){
if (jqXHR.status != 0){
window.location = <error page>
}
}
The second problem seems to stem around error handling of known errors (say invalid input). In this case I suggest the following workflow.
1) User clicks on edit button, taken to edit screen
2) User enters in data, use client side validation to do initial check
3) User submits, user is then taken to the view screen and is shown a
success or error message.
The server response could look like:
public ActionResult Edit(EditModel model){
if (!ModelState.IsValid)
{
return Json(new {successful = false, message = "Failed.."});
}
...
}
On the client side, your form callback should now handle the message and the fact it was successful or not. In my implementation, I used knockoutjs to create a "message" area that I could update and clear. (I created templates, etc).
Remember to use client side validation for the easy field validation stuff.... This will save a trip back to the server.
Yours could be quite simple, by popping up the message returned from the server.
Lastly, document ready only fires when the original document is done loading, never again for an ajax call (at least that is my understanding). Just put that code that is the document.ready at the bottom of the edit page. It will fire after the html it is targeting has already been rendered.
Hope that helps!

I have begun to move away from the asp.net views available in ASP.Net MVC due to some incompatibilities and/or unnecessary complexities when trying to achieve functionalities expected of AJAX enabled sites of the day.
I would recommend moving towards a design where you use "dumb" HTML files, use jQuery to download them using AJAX and drop them into a container (personally I use a div) and then use another AJAX call to gather the data from a controller. There are a number of advantages to this approach:
It establishes a real (not fake) separation between client side and server side code.
Html files can be cached on the client cutting down on the amount of data transmitted.
Binding of the Html elements becomes a client side task achieved using jQuery offloading processing cycles from the server.
Controllers essentially become collections of web methods which means they can be untilized by iPhone and Android apps making mobile deployment easier.
I realize this probably isn't the exact answer you're looking for and this may not be an option for you but my hope is that it will help someone at some point make a decision to move away from mixing HTML and server side code.

How far can I go with JavaScript?

I need to do as much as possible on the client side. In more details, I would like to use JavaScript to code an interface (which displays information to the user and which accepts and processes response from the user). I would like to use the web serve just to take a date file from there and then to send a modified data file back. In this respect I would like to know if the following is possible in JavaScript:
Can JavaScript read content of a external web page? In other words, on my local machine I run JavaScript which reads content of a given web page.
Can JavaScript process values filled in a HTML form? In other words, I use HTML and JavaScript to generate an HTML form. User is supposed to fill in the form and press a "Submit" button. Then data should be sent to the original HTML file (not to a web server). Then this data should be processed by JavaScript.
In the very end JavaScript will generate a local data-file and I want to send this file to a PHP web server. Can I do it with JavaScript?
Can I initiate an execution of a local program from JavaScript. To be more specific, the local program is written in Python.
I will appreciate any comments and answers.

It could technically, but can't in reality due to the same origin policy. This applies to both reading and writing external content. The best you can do is load an iframe with a different domain's page in it - but you can't access it programmatically. You can work around this in IE, see Andy E's answer.
Yes for the first part, mmmm not really for the second part - you can submit a form to a HTML page and read GET arguments using Javascript, but it's very limited (recommended maximum size of data around 1024 bytes). You should probably have all the intelligence on one page.
You can generate a file locally for the user to download using Downloadify. Generating a file and uploading it to a server won't be possible without user interaction. Generating data and sending it to a server as POST data should be possible, though.
This is very, very difficult. Due to security restrictions, in most browsers, it's mostly not possible without installing an extension or similar. Your best bet might be Internet Explorer's proprietary scripting languages (WScript, VBScript) in conjuction with the "security zones" model but I doubt whether the execution of local files is possible even there nowadays.

Using Internet Explorer with a local file, you can do some of what you're trying to do:
It's true that pages are limited by the same origin policy (see Pekka's link). But this can be worked around in IE using the WinHttpRequest COM interface.
As Pekka mentioned, the best you can manage is GET requests (using window.location.search). POST request variables are completely unobtainable.
You can use the COM interface for FileSystemObject to read & write local text files.
You can use the WScript.Shell interface's Exec method to execute a local program.
So just about everything you asked is attainable, if you're willing to use Internet Explorer. The COM interfaces will require explicit permission to run (a la the yellow alert bar that appears). You could also look at creating a Windows Desktop Gadget (Vista or Win 7) or a HTML Application (HTA) to achieve your goal.
Failing all that, turn your computer into a real server using XAMPP and write your pages in PHP.

see i got what you want to do
best things is do following
choose a javascript library (eg:jquery,dojo,yui etc), i use jquery.this will decrease some of your load
inspite of saving forms data in in a local file, store them in local variables process them and send them to server (for further processing like adding/updating database etc) using XMLHttp request, and when webservice returns data process that data and update dom.
i am showing you a sample
--this is dom
Name:<input type='text' id='name' />
<a href='javascript:void(0)' onClick='submit()'>Submit Form</a>
<br>
<div id='target'></div>
--this is js
function submit()
{
var _name=$('#name').val();// collect text box's data
//now validate it or do any thing you want
callWebservice(_name,_suc,_err);
//above call service fn has to be created by you where you send this data
//this function automatically do xmlHttprequest etc for you
//you have to create it ur self
}
//call this fn when data is sucessfully returned from server
function _suc(data)
{
//webservice has returned data sucessefully
//data= data from server, may be in this case= "Hello user Name"; (name = filled in input box);
//update this data in target div(manipulate dom with new data);
$('#target').html(data);
}
function _err()
{
//call this fn when error occurs on server
}
// in reality most of the work is done using json. i have shown u the basic idea of how to use js to manipulate dom and call servcies and do rest things. this way we avoid page-reloads and new data is visible to viewer

I would answer saying there's a lot you can do, but then in the comment to the OP, you say "I would like to program a group game."
And so, my answer becomes only do on the client side what you are able and willing to double check on the server side. Never Trust the Client!
And I do not want to do my job twice.
If you are going to do things on the client side, you will have to do it twice, or else be subject to rampant cheating.

We had the same question when we started our project.In the end we moved everything we could on the JS side. Here's our stack:
The backend receives and send JSON data exclusively.We use Erlang, but Python would be the same. It handles the authentication/security and the storage.
The frontend, is in HTML+CSS for visual elements and JS for the logic.A JS template engine converts the JSON into HTML. We've built PURE, but there are plenty of others available. MVC can be an overkill on the browser side, but IMO using a template engine is the least separation you can do.
The response time is amazing. Once the page and the JS/CSS are loaded(fresh or from the cache), only the data cross the network for each request.

Accessing URL executes JavaScript

I've coded an HTML page using jQuery for loading content. Now if I want to link directly to a submenu, is this possible to do with JavaScript?
So for example if someone goes to www.mydomain.com/submenu1/
then some JavaScript code will execute and load the needed contents?
Thanks a lot :)
Is it possible to realize that with htaccess?

You will more likely want to have a URL structure that only needs a page to load from the server once, then the server is only queried by JavaScript XMLHttpRequests. Loading content based on a "hard" URL would be pointless, since you're doing a server request anyways and might as well return the content in the response.
For keeping addresses unique while still keeping the "hard" URL the same (preventing multiple server requests), you can use the hash/anchor part of the URL. This means your address might look something like this: http://www.example.com/#/submenu1/
The #/submenu1/ part stays on the client, so only / on www.example.com is requested. Then it's up to your JavaScript to load the content relevant to /submenu1/. See a page of mine for an example of this: http://blixt.org/js#project/hash?view=code
Also have a look at this question: Keeping history of hash/anchor changes in JavaScript