[Solved] Special Character Input

Is there a way of preventing a user inputting special characters?

Hi @janaidfarooq34,

  • We will set the interval to 1 millisecond, Loops = True and Enabled = True:

  • And arrange the blocks like so:

Let me know how you get on with this :slight_smile:

Is there a way to do it where the user makes an input then presses a submit button which sends an alert to the user of an invalid/special character being inputted? I would show an image of what I mean but I having an issue screenshotting/uploading the image to you (it keeps saying access denied).

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Yes. The example here tells the user that you cannot enter % symbol.

Using these blocks and the Alert Component:

We achieve this result:

Hope this helps.

Thank you for the example. Is there a way to integrate more than one character so its like any special character entered can be detected?

Do you have a list of special characters?

you could put the list into a list, and loop through each 100ms instead of trhough each item specifically.

you could have the app take it out too


I will try this later thanks.

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@janaidfarooq34 let us know how you get on. This works on my end :slight_smile:

Will do

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Thanks, @eoinparkinson & @jared. It works nicely.


Hey, I am trying to include this with other input checks also. It doesn’t seem to work properly have I inputted the blocks incorrectly?

My Code Blocks:


I see a lot of ELSE IF statements here, what are these doing? The first IF statement looks fine to me.

Can you describe more about what is going on here? Maybe an example of the error/issue that you are receiving.


The first ELSE IF is to check for Special Characters in any of the 4 inputs (Name, Door/Flat No, Card No and Card Security Code). The 2nd one after checking for the 1st ELSE IF is to check for no input, 3rd one is for input length of 16 for Card No, 4th one for input length for Card No and the final one is to check for switches being enabled.

The ones after the 1st ELSE IF I have included so they are checked also. I think I have a rough idea where I have gone wrong do I need to include these ELSE IFs after the 1st IF statement?

If they all need to occur, i would nest one inside of the next.

Can you show me an example of how to do it just so I have a idea what to do.


I am still working on a solution for you, apologies for the delay on this.

Yh, I don’t mind who comes up with the solution as long as it functions as I want.