Yes I want to use OnChange event to validate input field (for blocking special characters)

You can do so by adding a new screen action to handle the "On Change" event, and add to the flow something like this:

Seeing your other reply, you can modify the code to include the RegEx search:

How to implement regex flag like "g and i" to check the repeated characters?

Please elaborate on what exactly do you want to achieve. You just want to check if a specific character is duplicated within a string, while ignoring the case-sensitivity? Some examples would be great.

This is my javascript code. Now I want to remove special characters from the following text so my output will be "test123". I want to know that how we can pass flags like "gi" in the pattern?

let stringToReplace = "test#123#$%##@";

var desired = stringToReplace.replace(/[^\w\s]/gi, "")

console.log(desired) //test123

1. Add the "Regex_Replace" as a dependency from the Text extension:

2. Configure it as such:

Example:

Basically I am using text field OnChange event and in that action I am using a JavaScript to validate keyboard keys (like to block special keys #, $ etc.) 

something like this

now out system giving me waring that event' is deprecated which is true as javascript will remove the event. So now how to pass event in the OnChange ?

https://developer.mozilla.org/en-US/docs/Web/API/Window/event

var regex = new RegExp("[a-zA-Z0-9]+$");var key = event.key;if (!regex.test(key)) {    event.preventDefault();}

var event: Event

@deprecated

'event' is deprecated.(6385)lib.dom.d.ts(18286, 5): The declaration was marked as deprecated here.

No quick fixes available

One more problem is that event.key will not work on the mobile keyboard. So how we can validate input field on mobile as well ?

You can use this javascript to prevent special characters in input field:

document.getElementById($parameters.WidgetId).addEventListener("keypress", function(e){    var patternNotOk = eval("^a-zA-Z0123456789]/g");   

 var text = this.value.replace(patternNotOk, '');    

if (this.value != text){        this.value = text;    }});

Try to use this JS and let me know if still the issue persists.

Thanks & Regards.

Thanks for now I implemented similar kind of solution.