Develop Reference

Low Bandwidth Website Design

A little while back, one of the junior developers at our company was tasked with creating a website for users to enter timesheets offsite. Mostly this is used for staff that reside offshore and have limited bandwidth (it's satellite internet, so we're already looking at a 500ms - 600ms response time, typically with only 10KB/s or less, including 10% - 20% intermittent packet loss).
So it's a challenging situation...
Recently I've been tasked with helping the junior to improve the speed and functionality of the website, mostly for my own benefit, since I'm usually a desktop dev. One thing I've noticed is that the website is using MultiView and I'm wondering if that's the best approach. I can see the reasoning; download the entire website once, then just make queries back and forth, showing/hiding the various views as necessary. Except it doesn't seem to work as smoothly as that.
95% of operations required a run by the server; i.e. add a new timesheet - need to tell the server, which in turn creates a new entry in the database. When the server is done, it seems to cause the client to download the entire webpage again, which is obviously counter productive.
So my question(s) are as follows;
Is this the expected behaviour, given the above situation? i.e. Should the entire webpage be getting re-downloaded once the server has completed it's actions?
If so, is this the best approach for the situation? Would it be better to have smaller, individual pages for the various features (timesheets/leave/etc.)?
I know this is probably a bit opinion based, but any ideas or assistance is greatly appreciated; for both our benefits.

Going from memory, Multiview only renders one of the views, not all of them, but since you mention the Multiview, that tells me you are using the older WebForms technology which often carries large amounts of overhead saving/restoring state. You can try and optimize that, especially if you are using some kind of grid control.
A better approach may be to ditch WebForms and switch to a newer technology like MVC. Rewrite the application to use AJAX with a webservice that returns JSON whenever possible to reduce the amount of data that needs to be sent to and from the server. Using MVC will also reduce the number of resources required for a page load (No resource.axd, etc) which will help page load times, especially over high latency links.
Make sure the server is set to compress dynamic pages with GZIP.
Compress and minify your javascript and CSS.
Don't use inline styles (the style attribute) in your HTML (use classes or IDs+children selectors) to reduce HTMLsize.
Bundle all your javascript and CSS.
Sprite your images in CSS where possible.
Run your images through a good image optimizer like http://kraken.io
Make sure you are caching whatever you can, and the cache duration is set properly.
Minify your HTML.
Stop using WebForms (or watch your page state, and control state very closely)
Check into some of the SPA architectures out there -- you may be able to make the whole application "offline-able" with the exception of the calls to get/update/create data.
Ultimately, each page should only require 1 HTML file, 1 CSS file, 1 Javascript file, and 1 sprite sheet on the first page hit, and then every page after that should only require a single HTML file.
You might also want to look into using a client side library like angular or knockout to handle rendering views. This can reduce the amount of traffic that needs to be sent (although it likely will increase the number of requests by one).

I think the best bet is a SPA (Single Page App) with Angularjs. Done right it greatly reduces the number of http requests. Navigation does not cause entire page reload in any case. Javascript files, css files etc, are loaded just one time at app load time. Once the app is loaded in the browser, the traffic is mainly sending JSON back and forth.
There are some tricks you should apply to reduce app load time:
Bundle javascript files into just one minified javascript file.
Bundle css files into just one css file.
Levearage http cache. You can use file versioning combined with MaxAge http header, so the browser does not even ask the server if the file has changed.
Some tools to help:
Fiddler, look at what is being cached and what isn't.
Facebooks augmented Traffic Control

To my understanding, ajax would be the best choice for you. If you want to access server 95% of times and reload the page with the new elements then the performance would hamper.
So instead of doing this make partial reloading with Ajax or Jquery. There are plenty of functionality available with jquery which would use ajax and reload specific portion of the webpage instead of whole page. It would increse the performance a lot.
One more thing I would like to add is that the response packet coming from server might be huge chunk. So instead of directly throwing the response from the server, implement GZip functionality in the website. It would compress the size of the data packet and the page would load/reload much faster.
Other than these, place your CSS and JS code inside some .css and .js file instead of placing it inside the page itself(and make sure to use it maximum time from all the pages). Browser would make a cache version of those files and reuse it instead of download it every time you want to connect to the server.

I believe that you have already figured out what's wrong. No Multiview is not good if it is implemented as is without tweaks. If your website uses viewstate and on top of that you have the multiview implemented, then it is going to be a costly affair.
Here are your options.
To use most out of the code, I would recommend to convert your methods HTTP GET / POST methods which can be then called separately from the needed actions in the html.
Don't re-render the entire page, but render the content which changes on menu action.
Change the non-changing part of your page / site to static content and apply compression on the static contents.
Enable page caching.
Cache the data offline wherever possible. (Remember it comes with a overhead of syncing data).
If you are considering a revamp give a thought about HTML 5 offline features.

Do I need to create thumbnails for WinRT application

I am coming from an asp.net background where if you want to display a photo gallery you have to have two files for each photo i.e. the original and a separate thumbnail file.
If I was to create a Win8App gallery that has say 100 photos per view. Would it be okay performance wise to simply change the size of the photo... i.e. only have the 1 file. (These are loaded from the file system).
I know it may depend on certain conditions but generally what is the best way to do it?

Depends on the file size, and where you get them from. If the files are on the system you could use StorageFile.GetThumbnailAsync. Otherwise, if the files are large and you are getting them from somewhere else (a service) you could load them only as they scroll into view for the user. Make sure to dispose objects as you are not using them as bitmaps are notorious for eating up memory resources.
100 images doesn't sound like a lot for me, but it's better to have numbers to back that statement up with as I have no idea how large the files are.
Here are some general guidelines for thumbnails from MSDN
I would try different ways to deal with it and use the performance tools to see what the end result is. Maybe you could group the images and have the user view one group at the time, maybe use placeholder images, or maybe the files aren't that big and its no problem at all to simply resize depending on view.
For lazy loading (recommended with many items) use data virtualization by implementing the ISupportIncrementalLoading You can find more information about that on MSDN.

10,000 + records on html to render quickly

Now this is going to be a very absurd question. But what can I do, it's the client's requirement. Basically, we have a grid (master-detail type) that goes up to about 15 thousand plus rows (has the potential to go up to 30-50 thousand rows in a few years time).
My client does NOT want any paging, does not want any data cropped as well. Also he isn't exactly using the latest hardware so rendering on browsers is a big issue. He wants to view everything by printing it out or looking through it on the browser. (You may all think how insane that sounds, and it sure is).
Now I want to resolve this issue by rendering html quickly. At the moment its a simple asp.net grid view w/o paging. That essentially renders HTML tables. My options that I think are:
- Manually rendering html using div (for quick loading)
- export it to pdf or excel (is there any way to export without the need to resort to third party controls?)
- give the finger (to the client :D j/k)
So to sum up, whats the best way to show 10,000 plus records of data on html?

consider using the "Scroller" plug-in for Datatables..
As part of DataTables 1.8 release a new plug-in called "Scroller" was
introduced as part of the download package. Scroller is an
implementation of virtual scrolling for DataTables, which presents a
vertically scrolling table, scrolling the full height of the table,
but drawing only the rows which are necessary for the visible display,
leading to a huge performance increase. This is quite an exciting
plug-in for DataTables not only for the performance increase, but also
because it effectively provide a new user interaction with the table,
allowing full scrolling of very large data sets.

I know this is almost a year late, but in case it helps someone.
Use SlickGrid - It uses divs instead of tables, which gives so much more performance in IE. Check this example

He wants to view everything by printing
This is imho the only viable solution to view all information. PDF or Excel is much better at handling a large number of rows.
Doing the rendering is quite easy. Just set the excel mime type and return a HTML table.
http://www.designdetector.com/archives/05/07/HTMLToExcelTheEasyWay.php
When it comes to PDF, you probably have to use an external library like PDFSharp.

You should do the paging - it does not mean that you need to show only one page of data at a time but rather you should retrieve and render pageful of data at a time (and keep continuously fetching pages one after one till data is finished).
For example, send the first page of data from the server in the initial request. Setup a js timer and use AJAX requests to retrieve subsequent pages of data and load that into the browser. You can have multiple (say 3-4) AJAX requests going on simultaneously for retrieving pages - only thing would be to achieve the ordering correctly in such approach.
I will personally avoid grid-view and render the html table using manual java-script (with help for jquery) or use some java-script template engine. I will use JSON for retrieving the data from the server.

Reducing Output Page Size Perfomance Improvement asp.net

I need to improve the speed of my website and perfomance.
I've tried everything under the book from compression handling , whitespace removal , update panels and enable view state false.. but nothing seem to work.
The output page size is still 764 kb.. which is quite a lot. So can you guys tell me an out of the box or any other way to approach this to decrease the output page size!

Put styles to external css files
Put javascript to external files
Try to use divs instead of tables for positioning
Short id names can help too :)
P.S.: it's difficult to advice without seeing the source

If it really cannot get further decreased, consider implementing some dynamic solution. You could first only load a main frame (without 'real frames') content page which afterwards loads more content dynamically. May use AJAX (javascript) controls or a custom solution for it.
Also, such big html code still looks strange. I doubt, the information can be (over)viewed at the same time by the user. She would at least have to scroll through some big tables or so? If you need a more smooth experience for the user, a dynamic solution may also show the content in chunks, dynamically loaded via javascript. Every time she scrolls down and a new part gets visible, that content is loaded from the server on demand.

If you are using Update Panels, try removing it. Alone Update Panel can load script file(s) which can be > 300 KB.

Best approach to show default image

Looking for information - I am creating a catolog website that includes a list of products. Each product has an image stored stored on the hard drive on the server. If the image does not exist, I want to show a default image. Whats the best way of doing this. I am using C# and considered checking on the server side if the image exists. But as some pages could have 50-60 images this would slow down the page. I use jquery on the client side. Any tips on this?

This is a great question, as the sitation arises in many circumstances. I see several options:
1) check for image availability during rendering of the catalog and use a link to the default image for items that do not have an image,
2) check for image availability in the image controller and return the default image when not available
3) put images inline in the document using data URLs
A major factor here is the possibility of caching.
Option (1) facilitates caching of the default image, but precludes caching of the catalog page. It is better if there are many items without an image, then such items will not even generate a hit to the server Furthermore, if there's a low chance that an image would appear for an item, you could cache the index too (for a reasonably short time).
Option (2) facilitates caching of the index page, but each image will have to send a request to the server. Again, you could use aggressive caching to avoid the same requests the second time the page is rendered.
Option (3) is best if your images are small and if the catalog page is relatively static. Be sure to use caching on the server side though while generating the page to reduce the load on the filesystem/database.

Sounds like this is a web application, so you should look into doing some caching. Even though image file lookups are expensive, once your page gets hit a few times the disk lookups will no longer be necessary.
Or you could store the information about whether a product image exists in your database. Then you prepopulate the database with the information and no disk checks are necessary.

Your best bet is to do this server-side as you suggest. You could do it client-side (attempt to load image, and load a default image if that fails), but this is not really what client-side scripting is designed for. You're making the user do extra HTTP requests, which is slower for the user.
An even better solution, as marcind suggests, is to pre-populate the database with default images. So in your CMS, when you create a new item, it assigns a default image URL to itself. You can then manually change it from there.

How does your jQuery code know the name of the image?
Seeing that your image files are physical files on the server and are accessible from a browser, I'd probably leave that part as is since that implies you don't have to serve the images yourself and IIS can handle that for you as a static file.
So your jQuery code obviously know the name of the image for each product. I assume this name is given to it by some server side process, so that process needs to give it either the name of the image for the product or the default image.
Some part of your code has to go through the process of figuring out if an image exists for the product and react accordingly. If you're using a database for your products that you could have a field in product table that indicates if the product has an image or not.