Re: reading from text area throwing exception with <p>

Hi Vikas,

ASP.NET 1.1/2.0 by default enable requestValidation so that any script or
html markup tags (like < , > ....) will raise runtime exception. For your
scenario, I think you can consider the following options according to
what's the exact behavior you want and what task will your web page
designed to do:

1.If you want to let client users input html/xml markup tags in entry
fields(textbox, ...) and just want to display them again (write out), you
can simply disable the "validateRequest" for that particular page(which
will accept html markup input) and then on server-side, use
Server.HtmlEncode or HttpUtility.HtmlEncode to encode the content in the
textbox. e.g

<%@ Page ..................... ValidateRequest="false" %>

string safeString = Server.HtmlEncode(TextBox1.Text);

Label1.Text = "<p>" + safeString + "</p">


2. Still turn on the "validateRequest", but peform valdation against the
Textbox's input content at client-side. For example, you can use a
customValidator control on the ASP.NET page to validate that certain
textbox in which the client user may input some html tags. And for the
custom Validator's client-side validation script, you can use javascript
function to check whether the input content contains those particular chars
(such as < , > .....).

3. Use the Textbox's client-side "onchange" event to perform the content
checking, in this case, the script checking will be performed everytime
after the client-user modify the content in the textbox.

Here are some articles discussing on peform content validation against
textbox entry field through javascript, you can replace those script
function with your own ones according to your validation requirement:

#Client-Side Form Verification with JavaScript
http://www.webdevelopersnotes.com/tips/html/restricting_visitor_input_from_a
_text_box_html_textarea_element.php3

http://webdeveloper.internet.com/javascript/javascript_form_verification.htm
l

#Using JavaScript to prevent or trigger form submission when ENTER is hit
http://www.cs.tut.fi/~jkorpela/forms/enter.html


#Checking/Validating Fields
http://www.irt.org/script/form.htm#5


Please feel free to let me know if there is anything unclear above or any
other information you wonder.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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