Is Null Or Empty(str Phone Num) Then Phone Valid = re Phone. Text) Then 'Call Phone Validation Function Message Box. I set up my Expression to allow only numbers, but in the format I explained earlier.
This exploit is typically referred to as a cross-site scripting (XSS) attack.
Request validation helps to prevent this kind of attack by throwing a "potentially dangerous value was detected" error and halting page processing if it detects input that may be malicious, such as markup or code in the request.
Sometimes people are just trying to be funny, or they are literally trying to break your program. If the data is indeed only alphabetic letters (no symbols, no numbers or any other punctuation characters) the test succeeds and stores True inside the Name Valid variable. This is because it becomes more legible than just a normal set of numbers.
You could say that a program's testers are supposed to do this; yes, they should - nobody else should. If not, if there is even just one unallowed character that is not supposed to be there, the Match method will return False. Instead of you having to loop through each character to determine what that character is, you simply need the correct Regular Expression pattern. Clear() Surname Valid = False Else Surname Valid = True End If End Sub It is basically the exact same code for the Name box, but I just included the capability to comprehend a space character as well. People expect to enter a phone number in a format similar to this: ###-###-####.
A name doesn't generally contain weird symbols, and definitely not numbers. This can be from the mouse clicking inside another field, or a Tab key being pressed to navigate to the next input control. ") Else Email Valid = True 'Email is Perfect End If Else 'Not A Match To Pattern Email Valid = False 'Set Boolean Variable To False Message Box. I hope you have learned from this article and that you have enjoyed it as much as I did.
That may seem like Captain Obvious speaking, but you'll be amazed at some of the data that gets entered into a name field. I then created an If statement to determine how the input data was formatted and whether or not the data is only alphabetic.
To ensure this is configured correctly request Validation Mode should be set to "4.0" (or not set at all) in web.config: There are enhancements added to request validation starting with ASP.
NET 4.5 that include deferred ("lazy") validation, the ability to opt-out at the server control level, and the ability to access unvalidated data.
This means that as a programmer, you have the power to supply the exact pattern for the input you desire in any text input field. Again, certain special characters are obviously not allowed.