常用的js对象扩展方法

1. 字符串的replaceAll

String.prototype.replaceAll = function(reallyDo, replaceWith, ignoreCase) {  
        if (!RegExp.prototype.isPrototypeOf(reallyDo)) {  
            return this.replace(new RegExp(reallyDo, (ignoreCase ? "gi": "g")), replaceWith);  
        } else {  
            return this.replace(reallyDo, replaceWith);  
        }  
    } 

2. 日起类型的format

Date.prototype.format = function (fmt) {
        var o = {
            "M+": this.getMonth() + 1,
            "d+": this.getDate(),
            "h+": this.getHours(),
            "m+": this.getMinutes(),
            "s+": this.getSeconds(),
            "q+": Math.floor((this.getMonth() + 3) / 3),
            "S": this.getMilliseconds()
        };
        if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
        for (var k in o)
            if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
        return fmt;
    }