var letters=' ABCÇDEFGÐHIÝJKLMNOÖPQRSÞTUÜVWXYZabcçdefgðhýijklmnoöpqrsþtuüvwxyz' 
var numbers='1234567890' 
var signs=',.:;@-\'' 
var mathsigns='+-=()*/' 
var custom='<>#$%&?¿' 

function alpha(e,allow) { 
     var k; 
     k=document.all?parseInt(e.keyCode): parseInt(e.which); 
     return (allow.indexOf(String.fromCharCode(k))!=-1); 
} 