javascript数值格式化函数

javascript数值格式化函数：

 

Number.extend({
    /*
    Property: numberFormat
        Format a number with grouped thousands.
 
    Arguments:
        decimals, optional - integer, number of decimal percision; default, 2
        dec_point, optional - string, decimal point notation; default, '.'
        thousands_sep, optional - string, grouped thousands notation; default, ','
 
    Returns:
        a formatted version of number.
 
    Example:
        >(36432.556).numberFormat()  // returns 36,432.56
        >(36432.556).numberFormat(2, '.', ',')  // returns 36,432.56
    */
 
    numberFormat : function(decimals, dec_point, thousands_sep) {
        decimals = Math.abs(decimals) + 1 ? decimals : 2;
        dec_point = dec_point || '.';
        thousands_sep = thousands_sep || ',';
 
        var matches = /(-)?(\d+)(\.\d+)?/.exec((isNaN(this) ? 0 : this) + ''); // returns matches[1] as sign, matches[2] as numbers and matches[3] as decimals
        var remainder = matches[2].length > 3 ? matches[2].length % 3 : 0;
        return (matches[1] ? matches[1] : '') + (remainder ? matches[2].substr(0, remainder) + thousands_sep : '') + matches[2].substr(remainder).replace(/(\d{3})(?=\d)/g, "$1" + thousands_sep) + 
                (decimals ? dec_point + (+matches[3] || 0).toFixed(decimals).substr(2) : '');
    }
});