XSLT is an XML-related technology which is used to transform XML data. XML file can be used to set the ground-rules for a given body of data and to describe the data itself. XSL allows us to take that input XML data and convert it into information which can be displayed in a web browser window or opened with a text editor. It can also be used to create an XML file which is a modified version of an input XML file.

When displaying elements in a browser window, the XSL elements which allow us to loop through an XML tree and carry out decision-making really come into their own. One of the key methods used in XSL for looping through all occurrences of a given XML element is the “For-each” element. This uses the “select” attribute to specify which XML element is to be used in the loop. The “For-each” element uses both an opening and a closing tag and any lines of code placed between the opening and closing tags will be repeated each time the element specified in the “select” attribute is encountered in the XML file.

For example, let’s say we have an XML file containing a list of companies and the addresses of their websites. Let’s also say that the element which we will be targeting in the XSL “For-each” statement is called “company” and that, within each company element, we have a “name”, “telephone” and “website” element. Before beginning our “For-each” loop, we could place the opening tag of an HTML “ul” element (an unordered or bulleted list).

Inside the “For-each” loop, we could output an HTML “li” element and, between its opening and closing tags, output the contents of the “name” and “telephone” elements from the XML file. The data in the “website” element in the input XML could be used to convert the “name” into a clickable link.

As regards the appearance of the data in the resulting HTML output, this would be controlled by a linked CSS file. CSS can be used to format the output in any way we desire, so our bulleted list can take on pretty much any appearance we care to give it.

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AJAX is one of the hottest internet technologies around. The best way to understand Ajax is to get an idea of what you can achieve with it, what it can do for your web development. Principally, Ajax can help you develop web pages and websites that function and respond like desktop applications. The Ajax technology achieves this by working away in the background, grabbing data from a server and then displaying it as it’s needed. As internet access speeds continue to increase, there will come a time when the user will not be able to perceive any difference between the performance of a web application and that of regular desktop software.

If you are an experienced web developer but have not started to delve into the world of Ajax, now is a good time to seriously consider finding some form of Ajax training.

Ajax-powered webpages differ from classic server-side pages in one important regard: with the classic page, to retrieve data from the server, the user normally has to submit information via the form and then wait for the page to reload and display a set of search results. With Ajax, interaction with the server can take place in a much more subtle manner, often without a form having to be submitted or the page having to reload.

The term Ajax is short for Asynchronous JavaScript and XML and Ajax involves the use of several web technologies. First of all, we have HTML and CSS, the raw material of which web pages are constructed. HTML defines the structure of the page content while CSS controls the layout and formatting of those elements. Next, we have XML data sources residing on a server. XML is a neutral standard for describing and storing information. Then there is JavaScript, the main scripting language used to add interactivity to web pages, which is used to fetch data from XML sources and use it to update the web page.

The most important element in JavaScript’s Ajax capabilities is the use of the XMLHttpRequest object which is used to send requests to the server without the need of refreshing the page. The key feature of this process is that it is asynchronous. This means that when a request is made for data from the server, the browser doesn’t need to wait for the data to come back. Therefore the page continues to function and when the data has been retrieved, the necessary parts of the page are updated.

Are you a web developer looking to expand you skill-set? If you are, you need look no further than Ajax. Ajax training will definitely enable you to take your web development expertise to a new level.

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ASP.NET includes a number of useful server controls which can be used by developers to quickly add sophisticated functionality to a web form. The server validation controls provided by ASP.NET are used to check the information entered by visitors to your site into form fields and display error messages if there are problems with the entries. This process is referred to as validation and is an essential part of the information gathering process. Validation requires that you lay down some ground rules for each of the key fields in your form. How strict these rules are how strictly you enforce them is up to you. You will probably want to strike a balance between rules which are not so lax that they allow users to submit rubbish via your form and not so strict that they put users off.

Some types of control are more likely to require validation than others. For example, text boxes in which the user can choose to enter any information they like is likely to require more checking than a check box which can be checked or unchecked and nothing else. In addition, some fields will require multiple validation checks while others will require only one or perhaps none at all.

The Microsoft ASP.NET validation server controls provide web developers with both server-side and client-side validation. Server-side validation takes place on the server and is usually implemented using one of the two main languages used in ASP.NET web development: VB.Net or C#. Client-side validation takes place in the user’s browser and is usually done using JavaScript, before the form is sent to the server.

There are benefits and drawbacks to both client-side and server-side validation. From the user’s point of view, client-side validation is quicker and also frees up the server to perform other tasks. However, it is in no way secure. It is easy for the user to look at the source code of the page and see what type of validation is being performed. It is also possible for the user to disable the execution of JavaScript within their browser’s preferences.

The drawbacks found with server-side validation are that it is slightly slower and uses more of the server’s precious processing power. However, it is secure and allows developers to set up validation procedures which users cannot side-step.

Since both client-side and server-side have definite benefits, it is usually best to implement both of them when creating forms. The validation server controls found in ASP.NET make this very doable and very easy.

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The ASP.NET environment offers a number of built-in solution for displaying information from a database. One of the simplest ways of displaying databound data on an ASP.NET web page is to add a GridView control. The GridView can be created simply by opening the Database Explorer and dragging the table or view that from which you want to display information. However, the default GridView which is automatically generated in this way almost always needs some tweaking. One typical change you may want to make is to change some of the BoundFields elements to TemplateFields elements.

BoundFields are the default container for displaying data from a given column in the data source. By contrast, any content you desire can be placed inside a TemplateField element. This makes it ideal for setting up validation through the use of validation controls.

TemplateFields may contain static HTML/CSS, ASP.NET web server controls as well as databinding statements. They also offer great flexibility by allowing you to include a variety of templates to cater for the different states of the conditions arising within the GridView. There are several types of template which may be added inside a TemplateField object; the main ones are described below.

The HeaderTemplate offers a way of customizing the information which will be displayed in the header of the column in which the TemplateField is located.

Use the ItemTemplate to hold the information which you want displayed for each row of data when the GridView object is not selected for editing.

Use the EditItemTemplate to hold the information which you want displayed for each row of data when the GridView object is in edit mode. It is here that you would place the controls necessary for validation.

Typically, you would display the information currently held in the database by adding a TextBox control inside the EditItemTemplate and databind it to the appropriate column from the data source using a statement like Bind(“FirstName”). Inside the same EditItemTemplate, you would then place the necessary validation control. For example, if you want to ensure that the field is not left blank when the form is submitted, you would insert a RequiredFieldValidator control.

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