A QueryString is a collection of characters input to a computer or web browser. A Query String is helpful when we want to transfer a value from one page to another. When we need to pass content between the HTML pages or aspx Web Forms in the context of ASP.NET, a Query String is Easy to use and the Query String follows a separating character, usually a Question Mark (?). It is basically used for identifying data appearing after this separating symbol. A Query String Collection is used to retrieve the variable values in the https query string. If we want to transfer a large amount of data then we can't use the Request.QueryString. Query Strings are also generated by form submission or can be used by a user typing a query into the address bar of the browsers. Syntax of Query String Request.QueryString(variable)[(index).count]
Advantages
* Simple to Implement
* Easy to get information from Query string.
* Used to send or read cross domain (from different domain).
Disadvantages
* Human Readable
* Client browser limit on URL length
* Cross paging functionality makes it redundant
* Easily modified by end user
