ASP Forms and User Input

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The Request.QueryString and Request.Form commands are used to retrieve user input from forms.

User Input

The Request object can be used to retrieve user information from forms.

Example HTML form

<form method="get" action="aspform.html">
First Name: <input type="text" name="fname" /><br />
Last Name: <input type="text" name="lname" /><br /><br />
<input type="submit" value="Submit" />
</form>

User input can be retrieved with the Request.QueryString or Request.Form command.

Request.QueryString

The Request.QueryString command is used to collect values in a form with method="get".

Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser's address bar) and has limits on the amount of information to send.

If a user typed "Bill" and "Gates" in the HTML form above, the URL sent to the server would look like this:

http://www.qctutorials.com/aspform.html?fname=Bill&lname=Gates

Assume that "aspform.html" contains the following ASP script:

<body>
Welcome
<%
response.write(request.querystring("fname"))
response.write(" " & request.querystring("lname"))
%>
</body>

The browser will display the following in the body of the document:

Welcome Mr.World

Request.Form

The Request.Form command is used to collect values in a form with method="post".

Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.

If a user typed "Bill" and "Gates" in the HTML form above, the URL sent to the server would look like this:

http://www.qctutorials.com/aspform.html

Assume that "aspform.html" contains the following ASP script:

<body>
Welcome
<%
response.write(request.form("fname"))
response.write(" " & request.form("lname"))
%>
</body>

The browser will display the following in the body of the document:

Welcome Mr.World

Form Validation

User input should be validated on the browser whenever possible (by client scripts). Browser validation is faster and reduces the server load.

You should consider server validation if the user input will be inserted into a database. A good way to validate a form on the server is to post the form to itself, instead of jumping to a different page. The user will then get the error messages on the same page as the form. This makes it easier to discover the error.


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