Allow only Alphabets in the textfield

Hi,



       function AllowAlphabet(e)
            {
                isIE=document.all? 1:0
                keyEntry = !isIE? e.which:event.keyCode;
                if(((keyEntry >= '65') && (keyEntry <= '90')) || ((keyEntry >= '97') && (keyEntry <= '122')) || (keyEntry=='46') || (keyEntry=='32') || keyEntry=='45' )
                    return true;
                else
                    return false;
            }
Usage :
 <input type="text" onkeypress="return AllowAlphabet(event)">