When users enter values into an HTML form, the values that they enter are strings.
In many cases, the values you need are some other data types, like integers or dates.
Its goal is to enable generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML.
XML has been designed for ease of implementation and for interoperability with both SGML and HTML.
This article discusses how to validate information you get from users — that is, to make sure that users enter valid information in HTML forms in an ASP. What you'll learn: If you ask users to enter information in a page — for example, into a form — it's important to make sure that the values that they enter are valid.
For example, you don't want to process a form that's missing critical information.
Each of the four numbers has a valid range of 0 to 255.
The following bash script contains a bash function which returns true if it is passed a valid IP address and false otherwise.
Please refer to the errata for this document, which may include some normative corrections.In bash speak true means it exits with a zero status, anything else is false.The status of a command/function is stored in the bash variable "$? variable so that rather than parsing words as whitespace separated items, bash parses them as dot separated.Even if users correctly enter an integer, for example, you might need to make sure that the value falls within a certain range.Important Validating user input is also important for security.