Update and rename specialcharacter.js to specialcharacter.js

- Moved the script to the new created folder in Regular Expressions.
- Refactored/fixed the code:
-- Renamed regex variable to disallowedChars for clarity.
-- Escaped special characters inside the regex to correctly match (, ), [, and ].
-- Added detailed comments explaining the purpose and structure of the regular expression.
-- Replaced placeholder field name with a variable for easier reuse and readability.
-- Improved error messaging to clearly inform users about invalid input.

Author: WillemZeiler

Client-Side Components/Client Scripts/Field Validation/specialcharacter.js

@@ -0,0 +1,24 @@
+function onChange(control, oldValue, newValue, isLoading, isTemplate) {
+    // Exit early if the form is loading, in template mode, or the new value is empty
+    if (isLoading || newValue === '') {
+        return;
+    }
+
+    /**
+     * Define a regular expression to match disallowed special characters.
+     * Breakdown of the pattern:
+     * [~@|$^<>*+=;?`'\)\(\[\]]
+     * * - Square brackets [] define a character class, meaning "match any one of these characters".
+     * - ~ @ | $ ^ < > * + = ; ? ` ' ) ( [ ] : These are the characters being checked.
+     * - Characters that have special meaning inside a character class (like `(`, `)`, `[`, `]`) must be escaped with a backslash `\`.
+     */
+    var disallowedChars = /[~@|$^<>*+=;?`'\)\(\[\]]/;
+
+    var fieldName = '<your_field_name>'; // Replace with the actual field name being validated
+
+    // Check if the new value contains any disallowed characters
+    if (disallowedChars.test(newValue)) {
+        g_form.clearValue(fieldName);
+        g_form.showErrorBox(fieldName, 'Special characters are not allowed.');
+    }
+}