A query string is a set of parameters passed along with the url to the web server. a query string stats with ? character and multiples values are passed using & character. a typical example of query string is given below

url?topicid=2&questid=10

They are based on browser. maximum length supported by internet explorer is 2048. tested results are saying that firefox, opera and netscape support more than 10000 characters

Advantages

very simple and easy to implement
no server resources are required
supported by all browsers

disadvantages

some browsers have a limit on maximum length supported
querystings can be easily tampered

Absolute expiration – in absolute expiration caching, cache object will be expired after the time set to this. for example if the time set is 5 minute, in every 5 minute cache object will be expired.

sliding expiration – in sliding expiration, if an object in cache is not accessed with in the specified time cache will be expired. when accessed it’s life will be extended for the same period again.

The process of submitting values from one .aspx page to another .aspx page is called cross page posting in asp.net. we can achieve cross page posting by setting postbackurl property of button

The process of submitting values from one .aspx page to another .aspx page is called cross page posting in asp.net. we can achieve cross page posting by setting postbackurl property of button