javascript to detect characters

sbkrohit · September 8th, 2008, 08:56 AM

Hello everyone

I need to check if the user types in any special characters like $ or & in a text filed and delete them automatically as soon as it is typed in.Is this posible using javascript?or should i wait till the user clicks the submit button and perform the regular validation?

Thanks in advance!

peirix · September 8th, 2008, 09:18 AM

Well, you can alwasy use onkeydown="checkCharacters();", which you can then set to do the check.

Then use indexOf to find the characters and delete them.

sbkrohit · September 8th, 2008, 10:09 AM

Thanks for the reply!

This is what I could come up with

<html>
<head>
<script>

function checkChar(e)
{
    var keynum;
    if(window.event) // IE
      {
          keynum = e.keyCode;
      }
    else if(e.which) // Netscape/Firefox/Opera
      {
      keynum = e.which;
      }
    if(keynum=16)
    {
        cnt=1;
    }
    if(keynum==55||keynum==61)
    {
        return false;
    }

}

</script>

</head>
<body>

<form action="">
First name:
<input type="text" name="firstname" onkeydown="return checkChar(event)">
<br>
Last name:
<input type="text" name="lastname">
</form>

</body>
</html>

The problem is that the shift press is also being treated as a event and when I click on number 7 for & ,the ascii code obtained is 55 which is for number 7 and not for & . So now 7 and & are not printing but I dont want only special characters.

Thank You