// ::::::::::::::: I S _ N U M B E R :::::::::::::::

function is_number(what) { 

	if(what.length==0) { return false; } 
	tmp = 0; 

	for (i = 0; i < what.length; i++) { 

		chr = what.charAt(i); 

		if ((chr >= "0" && chr <= "9") || chr == "." ) { 

			if (chr == ".") { tmp++; }
		
		} else { return false; }
	} 

	if (tmp > 1) { return false; } 
	return true; 
}