Develop Reference

Changing links based on mobile device

I have an HTML img tag with a static HTML link.
My idea is to dynamically change that link (but not the image) based on what type of device my user is connecting from. The major types of devices I am concerned with are PC, Google/Andriod, Ios, Amazon/Andriod.
Is there an HTML/CSS/Javascript solution to this, or is php/dom/server side the only options?

Javascript/JQuery will work for you. Let's say you used the code from here to detect different mobile browsers: http://www.abeautifulsite.net/blog/2011/11/detecting-mobile-devices-with-javascript/
Then you could write something like this:
if( isMobile.iOS() || isMobile.Android() ){
$('a#mylink').attr('href', 'http://newlink.com');
}

You might consider using CSS media queries for device sizes: http://css-tricks.com/snippets/css/media-queries-for-standard-devices/
OR you could use some sort of server-side detection library such as: https://code.google.com/p/php-mobile-detect/
OR you could use javascript: What is the best way to detect a mobile device in jQuery?

Programmatically "open in Adobe Reader" from JavaScript

The iOS safari browser has a handy option that appears whenever you open a PDF page in the browser
If you have Adobe Reader installed, a button will appear that says:
Open in "Adobe Reader"...
However, if you open up the PDF document where the HUD (address bar, etc) is hidden, like in a phone gap application, or a quick and dirty "Add to Home Screen app" using the following meta:
<meta name="apple-mobile-web-app-capable" content="yes" />
then, obviously, the button will not appear.
I want to still open the PDF document in Adobe Reader. Does anyone know a way to do this programmatically?
I want to include jsPDF in a phonegap application, and save the results, and this would be the easiest way to do that.
Thanks in advance!

With some fantastic help from Vince Parsons (and others), I've solved this problem.
Using a PhoneGap Plugin, you can create / expose a JavaScript call, which is then processed in Objective-c.
Here's the two lines you need (yes, only two lines!), and a subsequent explanation:
self.docInteractionController = [UIDocumentInteractionController interactionControllerWithURL:[NSURL fileURLWithPath:myDocumentPath]];
[self.docInteractionController presentOpenInMenuFromRect:CGRectMake(0,100,1,1) inView:UIApplication.sharedApplication.keyWindow animated:YES];
Explanation
Your input will be the file location.
In my case it's inside the app sandbox, so it looks something like:
/var/mobile/Applications/B16-HU83-GU1D-1D3NT1F13R/Documents/DocumentToExport.pdf
If you want to use an external URL, you can (with adjustments), but for my purposes it was internal.
So, with my file location as an input (let's call my input variable myDocumentPath), you just need to declare a document controller:
self.docInteractionController = [UIDocumentInteractionController interactionControllerWithURL:[NSURL fileURLWithPath:myDocumentPath]];
this creates a UIDocumentInteractionController using the interactionControllerWithURL method, which needs an NSURL variable.
We create that NSURL variable using the fileURLWithPath method, passing it our myDocumentPath.
The next line calls presentOpenInMenuFromRect Which takes a rectangle and a viewport:
[self.docInteractionController presentOpenInMenuFromRect:CGRectMake(0,0,1,1) inView:UIApplication.sharedApplication.keyWindow animated:YES];
the rectangle is created at position 0,0 with a width and height of 0,0 (GCRectMake(0,0,1,1))
and the viewport is taken from the PhoneGap application: UIApplication.sharedApplication.keyWindow
I'm reeling with joy and amazement that this only took two lines of code to fix. Granted, there's not a way to do it with JavaScript only, but it's still pretty elegant, and works great.

You can open your PDF using PhoneGap InAppBrowser(http://docs.phonegap.com/en/2.5.0/cordova_inappbrowser_inappbrowser.md.html#InAppBrowser) if the PDF is opend from the server using a URL or if its from local device, you can use the PDFViewer plugin: https://github.com/phonegap/phonegap-plugins/tree/master/iOS/PDFViewer.
Bothways the native default PDF reader will be used to open the PDF.

I really searched for an ready-to-use solution and gave up at one point. There are a few old repositories on GitHub and some articles building on the two lines of the green marked answer - but nothing works satisfying for me.
That's why i forked the cordova-plugin-file-opener2 to change the iOS behavior and this works perfect for me. To allow also parallel usage of the forked plugin, i've renamed it creatively to cordova-plugin-file-opener3. It provides the same features as version 2.0.1 of the forked plugin except that on iOS the "Open In"-Dialog is shown.
The change to the plugin was trivial. Just replaced one method call and did some renaming. Don't know why it was so hard to find a working solution - but maybe that i didn't search the right way.
You can find the repository here:
https://github.com/napolitano/cordova-plugin-file-opener3
Feel free to use it.

Switch web site to mobile css client side with JQuery

I am trying to change the display of my web pages depending on the version of the browser and space on screen. I need to completely change the look of the pages as follow:
If the site is displayed on a mobile phone I want the mini version.
If the site is displayed on a desktop browser but the size of the window is too small I want the mini version.
If the site is displayed on a desktop browser and the window can accommodate the full version I want the full version displayed.
If no javascript is available the full version should display.
I just started with some pretty basic code which relies on userAgent:
if( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) )
Is there a clean way to achieve what I'm trying to do with JQuery for example?

Use CSS media queries. Sniffing the user agent is not reliable, and will lead to maintenance headaches in the future. Also, using media queries means no javascript is required which is good from a separation of concerns point of view.

What should I use for my website mobile version ?jquery mobile / CSS3 page media / detecting browser size by jscript or redirecting to new page?

I have an personal profile website at http://www.kaidul.web44.net/ and I have used jquery, flash & high interactive component in it. But developing a small device version of it is becoming a challenge for me.It's page structure is based on jquery. I am now in fix in what should I approach ?
( jquery mobile / CSS3 page media / detecting browser size by jscript or redirecting to new page or anything else )
You can recommend me about it's structure whether I should modify it or not.
please help me.Thanks in advance.

My opinion is that you should do a redirect to a new page... because.. in the future you might want to modify something and will be difficult.. and another reason.. because is another view... Almost everybody is doing in a subdomain... and if the user want to view the desktop version... even if he is mobile.. redirect him to the large view...

Document Previews in Browser

Is there some way to preview documents in browser? Specifically in say an iframe within a page, as opposed to opening the doc in a new tab? I have a list of files of any type and when a user clicks on one, want to open it in a readonly format. If that file is a video or audio file, that's easy enough, but I'd like to be able to also do pdfs, word docs, maybe excel. Preferably it would be in a cross browser friendly way but if I need to do detection for a plugin (I've seen Google Docs Viewer for FF) I can live with that.
UPDATE:
ShaneC's answer is great and will work well in general. The one hitch I see is that for html5 devices (think ipad), I need to convert the document into a series of images. Is there any way for me to do this in an automated fashion? I need to be able to do this automatically when a new document is uploaded.

You'll want to integrate a cross-browser cross-type document viewer. Google will give you some good sites, personally I've had good experiences with Flex Paper.
For demos, see here: http://flexpaper.devaldi.com/demo/

There is another approach that can be used to view images/pdf/xlsx/docx etc.
You can use iframe and google's gview in the following way:
const YOUR_URL = https://calibre-ebook.com/downloads/demos/demo.docx;
<iframe
className="doc"
src={`https://docs.google.com/gview?url=${YOUR_URL}&embedded=true`}
/>

There is the Javascript ViewerJs. An open source tool which allows a website to display PDF and open standard for office documents. It will display the documents inline and without browser plugins.