Section 1 - JavaScript

JavaScript is an object-based scripting language for developing Internet applications. JavaScript is meant to tell an application what to do. Unlike languages used to create applications, it cannot do anything without the application. JavaScript is an extension to HTML that allows you to create more sophisticated Web pages than you could with HTML alone.

For example, my last project (an Internet booking screen) I needed to program events against user actions. For instance page navigation, the highlighting of input boxes when focused, detecting key press or key values, server-side report generation, search routines accessing dynamic arrays etc.

Cross Browsers
Years gone by Netscape was always my preferred choice of browser, if you asked me why I might have replied because Microsoft appeared overbearing and almost forced you to use their product. I seem to recall Netscape did the same thing with Mosaic but you didn't hear too much about it.

How times have changed, I now write commercial web applications which require interactive responses from user actions and predefined page layout. Using MSIE this is easily accomplished, however try it with Netscape and retain sanity. Just to make it more annoying, try creating identical pages for Win32 Netscape (4) and Linux Netscape (4). The Linux version doesn't support half the functionality of the Win32 version. I spent so much time just making the Netscape pages look and behave the in the same manner, something which was so easy with Microsoft's Internet Explorer.
If I were asked to write another application for Netscape I would have to think twice about it !!

Section 2 - CSS - Cascading Style Sheets

CSS is a new standard for making web pages. The main difference with HTML is that in CSS you don't have to describe each of the same elements over and over, no matter how many pages you access they all reference the same CSS script thus reducing the overall size of each page and making them load faster. For instance most of the colour and text properties of these pages are controlled by CSS.
There is however a drawback, because CSS is still very new, it's not supported by old browsers and to make matters worse Netscape Navigator and Microsoft Internet Explorer support different tags. So it's not advisable to use only CSS in your documents, you can however program using JavaScript to write the Style parameters dependent on browser platform and restrict old browsers trying to read your CSS Style tags by enclosing them within comments tags.

Section 3 - ASP & PHP

Active Server Pages. ASP enables server-side scripting for IIS with native support for both VBScript, Jscript or Javascript.

PHP (Hypertext Preprocessor) also allows you create dynamic web pages that can display a variety of data, both ASP or PHP web pages often work in conjunction with a database of information they draw from.

I originally used ASP as the primary means to retrieve data from the SQL server (reports or general information), I then discovered that PHP does it just that little bit better and is less platform dependent.

Currently I have IIS installed on my home computer and run both ASP and PHP pages in a local intranet environment to test various database and graphics routines.

Section 4 - Visual Basic & SQL

Before I started writing commercial web pages, I was employed as a System Analyst interpreting other programmers code and converting it into Visual Basic applications. It's funny to think that some of the database scripts I wrote then are now being used in web pages. Visual Basic is a high level programming language it is a visual and events driven Programming Language. By this I mean VB is programming in a graphical environment. Because users may click on a certain object randomly, so each object has to be programmed independently to be able to response to those actions(events). Therefore, a VB Program is made up of many subprograms, each has its own program codes, and each can be executed independently and at the same time each can be linked together in one way or another.

Structured Query Language (SQL) allows users to access data in relational database management systems, such as Oracle, Sybase, Informix, Microsoft SQL Server, Access, and others.
What do we use SQL for? Well, for example we can use it to select data from the tables located in a database.

The most basic SQL structure is:

SELECT "column_name" FROM "table_name"

To illustrate the above example, assume that we have the following table:

Table Employees

employee	section	joined
Bill	Sales	15-05-1999
Fred	Sales	01-07-1999
John	Admin	10-08-2000
Ray	Store	23-09-2000

To select all the employees in this table, we key in,

SELECT employee FROM employees

Result:

employee
Bill
Fred
John
Ray

We could now try to put a condition on our query, like only return the employees from the sales section.

SELECT employee FROM employees where section = 'sales'

Result:

employee
Bill
Fred

As you can see this is just a very simple example of what is possible, I haven't mentioned combining different tables using the join commands or table editing. There are many good publications on SQL and database connectivity, such as Sams Publishing 'SQL Unleashed' which is a reasonable book with good practice examples.
SQL strings can become quite large, the example below is from one of my web report programs. In this program I set up a parameters page where clients can modify the way a report is presented by selecting or not selecting nominated fields for the final display.
When scripts get this large and complicated using a query analyser to test the string makes life a lot easier especially when your statement is not quite right and needs modification.

SELECT Top 50 Jobs.AuditID, Jobs.Status, Jobs.ClientID, Jobs.Cancelled, Jobs.CompanyID_book, Jobs.CustomerID , CONVERT(varchar, Jobs.Booking_date, 106) AS [Date] , Jobs.Booking_number , OrigAddress = (select details from jobaddressinfo where jobaddressinfo.auditid = jobs.auditid and jobaddressinfo.legnum = 0) , Origsuburb = (select [name] from suburb where suburb.suburbid = (select suburbid from jobaddressinfo where jobaddressinfo.auditid = jobs.auditid and jobaddressinfo.legnum = 0)), DestAddress = (select details from jobaddressinfo where jobaddressinfo.auditid = jobs.auditid and jobaddressinfo.legnum = (jobs.legs)) , Destsub = (select [name] from suburb where suburb.suburbid = (select suburbid from jobaddressinfo where jobaddressinfo.auditid = jobs.auditid and jobaddressinfo.legnum = (jobs.legs))), CONVERT(varchar, Jobs.Time_booked, 102) AS Booked, Completed = CASE WHEN Jobs.Time_completed > CONVERT(datetime, '1970-01-02', 102) AND Jobs.tandc = 0 THEN CONVERT(varchar, Jobs.Time_completed, 100) WHEN Jobs.Time_completed > CONVERT(datetime, '1970-01-02', 102) AND Jobs.tandc != 0 THEN 'Delivered' WHEN (SELECT TimeReported FROM JobaddressInfo WHERE JobAddressInfo.AuditID = jOBS.AuditID AND JobAddressInfo.LegNum = 0) > CONVERT(datetime, '1970-01-02', 102) THEN 'Picked up' ELSE 'Booked' END, convert(varchar, Jobs.TotalFee, 1) as TotalFee, convert(varchar, Jobs.TotalFee + Jobs.GST_fee, 1) as TotalFeeinc, Jobs.Goods, Jobs.Reference, Jobs.Reference2, Jobs.Caller, jobs.legs, POD = (select authorisation from jobaddressinfo where jobaddressinfo.auditid = jobs.auditid and jobaddressinfo.legnum = (jobs.legs)) FROM Jobs WHERE ((Jobs.CustomerID = 83913188) and (Jobs.CompanyID_Book = 1)) and (jobs.Dont_invoice = 0 or jobs.test_account <> 0) and jobs.time_booked <= '2001-08-15 23:59:59' and jobs.time_booked > '2001-07-16 23:59:59' order by jobs.Time_booked desc