Develop Reference

Clientside PostgreSQL Javascript access without serverside part

I know that direct access to a database via Javasript is not recommended, since the user would get the database login and thus the ability to manipulate the database.
But in my case, the user cannot see the client-side code, since it's a phonegap app.
Is there a way to do it? And it not, what is a good way to do with a serverside part?

its really not recommened to access database from client-side its not only for security reasons, but what if you changed the database access or upgrade to different database, so you will have to change it in your app which you may not be able to access again after users installed if its mobile app and then you stuck to your database for ever,
so whatever you want to do you can add an action in server-side and depend on your params it will formulate your Query,
for example sending parameter for user=true this will search for users tables, sending parameter for account=true will search in users-accounts tables and so on.

How to submit a form internally?

I am curious about submitting a form data internally.
Here is an example.
I want to register an account for a website. The website will give a form to register which upon submitting will create an account for me.
But I don't want to go to that site. Instead I'll give a form in my style and collect the same information. Upon submit, I want to create the account automatically. Automatically in the sense, I'll submit the form internally.
The reason why I need this feature is, I don't want my users to create a separate account in another website also. I mean it should save user's time in creating account only. Rest of the things will be taken care by me.
Please let me know if anyone had tried this and had success.
I know it is very difficult for existing accounts and some internal errors. But I also need to track them.
Please let know if this is possible or not.
An Example
There is site called othersite.com which has a form for creating / registering users.
I will a similar form to the user on mysite.com. But upon submit the form information is sent to both mysite.com and othersite.com. Both sites create accounts parallelly with a single form submission.

Unless you are working with AJAX requests and CORS enabled sites, which I assume is not the case, client side technologies ( browser/javascript ) will not help you much to do that.
You have to ask yourself what are the options to integrate with the second site in order to automatically create the account. Following some common patterns used these days:
REST API: You have an url where you can use HTTP to talk to and ask to create the account. Many social networks and other popular services usually expose it. Facebook API
Database: Although it is less recommended you could just insert a new record into the account table if you own and have access to the database used by the second site.
Client Libraries: Some sites provide client libraries so that you can use them together with your project code base. Eg: Twitter Libraries

Securely Passing UserID from ASP.Net to Javascript

In the application I am currently developing we are using ASP.Net forms authentication to grant the user further access to the site. This site is targeted towards mobile users and as such we are attempting to be as hands off from the server as possible and make use of KnockoutJS to make the web service call and load the data so that the user can view it.
Right now the webservice (REST service using GET method) requires the username in order to load the data specific to that user. I have this information on the server side (ASP.net) and I can easily access either User.Identity.Name or access the forms authentication cookie directly and pull the information.
My problem is that I need to get the username from the server to the client so that the service call can be made. I have looked into doing this securely but so far have come up blank. Currently I am passing the username as a url parameter and parsing it out using JavaScript, with a check on the Page_Load method to verify the username in the url matches the logged in user.
I need a way to secure pass a username from ASP.Net that has authenticated the user using form to the client side JavaScript so I can make a REST webservice call.
EDIT: So after googling and meeting with my team lead I think we will be using an OAuth implementation similar to this example:
http://www.c-sharpcorner.com/UploadFile/surya_bg2000/secure-wcf-restful-service-using-oauth/
Also for anything else looking for the same answer I found this question very helpful in understanding OAuth:
What's the point of a timestamp in OAuth if a Nonce can only be used one time?
Assuming everything is implemented correctly would it be more secure (totally secure, secure, or more insecure?) to instead pass the generated signature via an ASP tag as mentioned below?
EDIT 2: After some more review and some more searching we finally decided on a framework and method of making this work. As it turns out OAuth isn't necessarily the answer here, this questions:
But Seriously.... Example of ASP.NET WebAPI implementation including OAuth
was a lot of help as well in figuring out how to make this work. What we are going to end up doing is generating the signature and putting in on the javascript and making the call like that. The signatures are going to be time sensitive and regenerated each time the user loads the page so very OAuth like but we arent implementing the full spec.
TL:DR Final solution was to generate a hash signature and put it on the page via ASP server tag <% aspvar_here %> and use it to validate the service call

Simplest way would be to render this javascript in your page:
<script type="text/javascript">
window.UserID = '<%=HttpUtility.JavaScriptStringEncode(this.User.Identity.Name)%>';
</script>
Now you can reference it in your JS.
But, more importantly, if this user id is not used just as a default parameter but instead to authenticate the user, this is a security hole. Normally the REST service should also be able to look at User.Identity.Name instead of receiving it as a argument.

Normally the username is provided by the client to begin with. It is then verified on the server-side (using whatever authentication is necessary, such as a password).
If it has been verified on the server side (in your case, this must be from a WCF web service as ASMX does not cope well with REST), then you can be sure that it is correct - plus you already have the username on the client-side.
EDIT:
As Knaģis pointed out, you can get it using an ASPX tag, presuming the page is an ASPX page and not HTML.

If you just want to have the username in the client side, the other answers explain how to do this.
But as you stated, this IS a security risk. Someone can modify the data on the client and impersonate another user.
The correct way to do this:
After a user successfully logs in, a Guid is issued which uniquely identifies this user.
The Guid is the token which is saved on the client and passed to the server not the username.
All webservices receive the Guid not the username.
Server has a dictionary which converts the Guid to the original username.
Another option can be to encrypt the username and pass the encrypted value to the webservice. The webservice will need to decrypt the value in order to get the username .

Store product details from URL

Is there a method or is it even possible to get a products details by using a URL. Let's say I paste a URL of a product from a store like Walmart Or bestbuy, would it be possible to write something to retrieve the product info (price, name, info, etc..) does this exist? Or would this have to be something site specific that I can write for each specific store?

One solution I see is to parse the HTML code of the page the URL redirects to using for example Tika, but I'm not sure the e-commerce website in question will like that very much :) Maybe you could ask them if they have implemented an API to access their products data?

Yes, it is possible, but not using JavaScript due to same-origin-policy. You must send that URL to the server, read that external page on the server side and return results back to the server.
On the server side (in whichever language you are using) download the web page, parse it (using xml/xpath if you can) and extract relevant information.
As already noted watch out, some websites forbid such access (called web-scraping), other might actively try to prevent that, e.g. by discovering fake clients.

What you're talking about is website scraping and yes, it's possible and there are loads of tools out there to help you with it. Some websites aren't happy with you doing it though.
You could do it in C# using the HttpWebRequest class to request data from a url and then parse it with something like XmlReader or the http://html-agility-pack.net/

What is a good way to get feedback from a user on a website?

I'm working on a website for my county's fair. I want to allow my visitors to be able to ask me questions by inputing their name, email, and comment in a form like this one:
http://lincolnfair.net/images/feedback.JPG
So I guess my real question is how can I send an email (using JavaScript/JQuery) to myself with all these fields as the main body of the email.

You should use a server-side script (e.g. PHP, Python, Perl, etc.). With pure HTML and JavaScript, you can use a mailto form, but this will be very unreliable.

I will suggest uservoice.com , it can integrate with your site nicely, a much more powerful user feedback system, without spending time to code the feedback system yourself

As others have indicated, this is a typical task that can be solved easily using a server-side language. Javascript and jQuery aren't the right tool for this particular problem. To point you in the right direction, use method="post" for your form, and you can access users' submission in a PHP file by examining the $_POST variable. If a <input> element in your form has name="email" in your email, you can access that variable in PHP as $_POST['email']. If you're interested in a PHP solution, look at the documentation for the mail() function.

Jukka has a good guide on How to write HTML forms. It should give you everything you need to produce something functional.
You need a server side component, nothing client side will be a reasonable substitute for that. JavaScript won't help for a form as simple as the one you describe.

The most reliable way will be to use a server side script in your preferred language. The specifics of how to do this are probably outside the scope of this question and would depend upon your language of choice.
Your other option is to set the action of the form as a mailto: which will use the visitors preferred email client to send the email. This will work but is really bad and relies on the viewer having an email client installed and configured.
you can find out more information about the mailto option at http://www.chami.com/tips/internet/010597I.html
Another good option would be a third party site such as www.wufoo.com which handle all of the email business server side for you on their own servers. I believe Wufoo even allow you to embed their forms within your own site.

If you want it to be available on every page, you might want to consider using jQuery and the UI Dialog plugin. You could set it up so that the default feedback is a mailto which gets replaced using javascript with a link that brings up a jQuery Dialog containing the fields you want to collect. This could be submitted back to your server via AJAX and delivered to you via email from the server.
EDIT: Since you've edited your question to indicate a server-side only solution, the above seems somewhat out of context. With others, I would agree that using some client-side code to actually send the email is the way to go (as alluded to above). I think it's preferable to use your own server for this, but I'm sure that you can find many "form to email" services. I would avoid these, unless you want your email addresses harvested for use in SPAM. You might also be able to use a signed applet or ActiveX control for this, again I would not go down that route. As indicated above, I would let the browser handle the interface, but my server handle the sending of the email.

I am not sure i understand your question completely, but if all you want to do is conduct a survey over email, i don't think you need to use jQuery or HTML.
A very simple way to do it is to use the 'Forms' feature in Google Docs.