function isLetter (c) {
	return ( ((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")) || c == " " );
}

function isDigit (c) {
	return ((c >= "0") && (c <= "9"));
}

function isLetterOrDigit (c) {
	return (isLetter(c) || isDigit(c));
}

function asc ( tString ) {
	return tString.charCodeAt ( 0 );
}

function chr ( nValue ) {
	return String.fromCharCode ( nValue );
}

function upperChar ( c ) {
	c=asc ( c );
	if ( c >= 97 && c <= 122 )
		c -= 32;
	return ( chr ( c ));
}

function lowerChar ( c ) {
	c=asc ( c );
	if ( c >= 65 && c <= 90 )
		c += 32;
	return ( chr ( c ));
}