// ----------------------------------------------------------------------------
// scr_Utils
// ----------------------------------------------------------------------------
 
function PrepareNumber(number)
{
	var result = '';
	var valid_chars = '+0123456789';
 
	var number_length = number.length;
	for (var i = 0; i < number_length; i++)
	{
		var ch = number.charAt(i);
		var found = valid_chars.indexOf(ch) != -1;
		if (found)
			result += ch;
	}
 
	return result;
}
 
function Substring(str, index)
{
	var length = str.length;
	var new_length = length - index;
 
	return str.substr(index, new_length);
}
 
function StartsWith(str, pattern)
{
	var pattern_length = pattern.length;
	if (pattern_length > str.length)
		return false;
 
	var found = false;
	for (var i = 0; i < pattern_length; i++)
	{
		if (str.charAt(i) != pattern.charAt(i))
		{
			found = true;
			break;
		}
	}
 
	return !found;
}
 
function DigitsFromString(number) {
	var prepared_number = PrepareNumber(number);
 
	var city_code = '+74212';
	if (StartsWith(prepared_number, city_code))
		return Substring(prepared_number, city_code.length);
 
	var country_code = '+7';
	if (StartsWith(prepared_number, country_code))
		return '8' + Substring(prepared_number, country_code.length);
 
	return prepared_number;
}