Don’t Allow Special Characters in Textbox Javascript

by

Whenever we create a contact form or user form. We want that no user should input a special character, because there may be a hacking script. Which can destroy or hack our database or project file.

In this blog post, we will learn how don’t allow special characters in textbox javascript. First, make a textarea in HTML.

HTML

<!DOCTYPE html>
<html>
    <head>
        <title>Don't Allow Special Characters in Textbox Javascript</title>
    </head>
    <body>
       
         <form id="frm" runat="server">
     
                 <textarea name="folderName"  onkeypress="return blockSpecialChar(event)"></textarea>
      
         </form>

    </body>
</html>

Here I using onkeypress, The onkeypress property of the GlobalEventHandlers mixin is an event handler that processes keypress events.

Javascript

 <script type="text/javascript">
    function blockSpecialChar(e){
        var k;
        document.all ? k = e.keyCode : k = e.which;
        return ((k > 64 && k < 91) || (k > 96 && k < 123) || k == 8 || k == 32 || (k >= 48 && k <= 57));
        }
  </script>

Another method

 <script type="text/javascript">

         function blockSpecialChar(event){
            if(!((event.keyCode >= 65) && (event.keyCode <= 90) || (event.keyCode >= 97) && (event.keyCode <= 122) || (event.keyCode >= 48) && (event.keyCode <= 57))){
               event.returnValue = false;
               return;
            }
            event.returnValue = true;
         }

      </script>

Hope this code will be helpful for you.