Don’t Allow Special Characters In Textbox Javascript

To not allow special characters in a textbox using JavaScript, you can use regular expressions to validate the input. Here’s an example of how you can accomplish this:

    <label for="myTextbox">Enter text without special characters:</label>
    <input type="text" id="myTextbox" oninput="validateInput()">
    <div id="error" style="color: red; display: none;">Special characters are not allowed!</div>

    <script>
      function validateInput() {
        var textbox = document.getElementById("myTextbox");
        var error = document.getElementById("error");
        var regex = /^[a-zA-Z0-9]+$/; // Regular expression to allow only alphanumeric characters

        if (!textbox.value.match(regex)) {
          error.style.display = "block";
          textbox.value = textbox.value.replace(/[^a-zA-Z0-9]/g, ""); // Remove special characters from the input
        } else {
          error.style.display = "none";
        }
      }
    </script>
  

In the above example, the textbox has an “oninput” event handler that calls the “validateInput” function every time the user types something. The function checks if the input contains any special characters using a regular expression.

The regular expression “/^[a-zA-Z0-9]+$/” allows only alphanumeric characters (letters and numbers) and ensures that all characters in the input match this pattern. If the input contains any special characters, the function displays an error message and removes the special characters from the input value using the “replace” method.

The error message is initially hidden with the “display: none;” CSS style. If the input is valid (no special characters), the error message is not displayed.