The Query String helps in sending the page information to the server.

The Query String has the following advantages:
• Every browser works with Query Strings.
• It does not require server resources and so does not exert any kind of burden on the server.

The following are the limitations of Query String:
• Information must be within the limit because URL does not support many characters.
• Information is clearly visible to the user, which leads to security threats.

When a browser requests an .aspx file then the server returns a response, which is rendered into a HTML string

The ValidationSummary control displays all validation messages in one control.

The two new properties added in the Page class are MetaKeyword and MetaDescription.

Tracing displays the details about how the code was executed. It refers to collecting information about the application while it is running. Tracing information can help you to troubleshoot an application. It enables you to record information in various log files about the errors that might occur at run time. You can analyze these log files to find the cause of the errors.

In .NET, we have objects called Trace Listeners. A listener is an object that gets the trace output and stores it to different places, such as a window, a file on your locale drive, or a SQL Server.

The System.Diagnostics namespace contains the predefined interfaces, classes, and structures that are used for tracing. It supplies two classes, Trace and Debug, which allow you to write errors and logs related to the application execution. Trace listeners are objects that collect the output of tracing processes.