javascript string對象格式化的方法

    javascript string對象格式化,下面是參考代碼：
    /**
    * 字符串格式化，類似于java中的MessageFormat.format() 函數(shù)
    * e.g.
    * 'This is a {0} not a {1}.'.format('string', 'num') => This is a string not a num.
    * 'This is a {0}, not a {1}. so parse to {2} first.'.format('string', 'num', 'num') => This is a string not a num. so parse to num first.
    * 'This is a {0}, not a {1}. so parse to {1} first.'.format('string', 'num') => This is a string not a num. so parse to num first.
    * 'This is a {0}, not a {1}. so parse to {2} first.'.format('string', 'num') => This is a string not a num. so parse to {2} first.
    */
    String.prototype.format = function() {
    var args = arguments;
    return this.replace(/\{(\d+)\}/g, function(){
    var val = args[arguments[1]];
    alert(val + ' ' + arguments[0]);
    return (! val) ? arguments[0] : val;
    });
    };