how to do validations using javascript in asp.net

function isAlphaOrParen(str) {
  return /^[a-zA-Z()]+$/.test(str);
}
Modify the regexp as needed:

/^[a-zA-Z()]*$/ - also returns true for an empty string
/^[a-zA-Z()]$/ - only returns true for single characters.
/^[a-zA-Z() ]+$/ - also allows spaces

<script type = "text/javascript">

function isAlpha(keyCode)
{
   return ((keyCode >= 65 && keyCode <= 90) || keyCode == 8 )
}

</script>