<script src="Js/jquery-3.1.1.min.js"></script>
    <script type="text/javascript">
        /*
        * 格式化金额 个位起每三位逗号分隔 10,000.00
        * @param n 小数位
        * @return
        */
        String.prototype.toThousands = function (n) {
            var n = n > 0 && n <= 20 ? n : 2;
            var s = this;
            s = parseFloat((s + "").replace(/[^\d\.-]/g, "")).toFixed(n) + "";
            var l = s.split(".")[0].split("").reverse(), r = s.split(".")[1];
            t = "";
            for (i = 0; i < l.length; i++) {
                t += l[i] + ((i + 1) % 3 == 0 && (i + 1) != l.length ? "," : "");
            }
            return t.split("").reverse().join("") + "." + r;
        }

        /*
        * 类似C#中string.format函数
        * @return
        */
        String.prototype.format = function () {
            var result = this;
            if (arguments.length == 0)
                return null;
            for (var i = 0; i < arguments.length; i++) {
                var re = new RegExp('\\{' + (i) + '\\}', 'gm');
                result = result.replace(re, arguments[i]);
            }
            return result;
        };

        /*
        * 返回字符的长度,一个中文算2个
        * @return
        */        
        String.prototype.strLength = function () {
            return this.replace(/[^\x00-\xff]/g, "**").length;
        };

        /*
        * 判断字符串是否以指定的字符串开始
        * @return
        */       
        String.prototype.strStartsWith = function (str) {
            return this.substr(0, str.length) == str;
        };

        /*
        * 判断密码安全级别
        * @return
        */
        String.prototype.checkPassWordLevel = function () {
            var n = 0;
            if (/\d/.test(this)) n++; //包含数字  
            if (/[a-z]/.test(this)) n++; //包含小写字母      
            if (/[A-Z]/.test(this)) n++; //包含大写字母   
            if (this.length <= 6) n = 1; //长度小于等于6位  
            return n;
        }

        /*  
        * 检索数组元素(原型扩展或重载)  
        * @param o 被检索的元素值  
        * @returns 元素索引  
        */
        Array.prototype.contains = function (o) {
            var index = -1;
            for (var i = 0; i < this.length; i++) { if (this[i] == o) { index = i; break; } }
            return index;
        }

        /*
        * 日期格式化(原型扩展或重载)  
        * 格式 YYYY/yyyy/YY/yy 表示年份  
        * MM/M 月份  
        * W/w 星期  
        * dd/DD/d/D 日期  
        * hh/HH/h/H 时间  
        * mm/m 分钟  
        * ss/SS/s/S 秒  
        * @param {formatStr} 格式模版  
        * @returns 日期字符串  
        */
        Date.prototype.formatDate = function (formatStr) {
            var str = formatStr;
            var Week = ['日', '一', '二', '三', '四', '五', '六'];
            str = str.replace(/yyyy|YYYY/, this.getFullYear());
            str = str.replace(/yy|YY/, (this.getYear() % 100) > 9 ? (this.getYear() % 100).toString() : '0' + (this.getYear() % 100));
            str = str.replace(/MM/, (this.getMonth() + 1) > 9 ? (this.getMonth() + 1).toString() : '0' + (this.getMonth() + 1));
            str = str.replace(/M/g, this.getMonth());
            str = str.replace(/w|W/g, Week[this.getDay()]);
            str = str.replace(/dd|DD/, this.getDate() > 9 ? this.getDate().toString() : '0' + this.getDate());
            str = str.replace(/d|D/g, this.getDate());
            str = str.replace(/hh|HH/, this.getHours() > 9 ? this.getHours().toString() : '0' + this.getHours());
            str = str.replace(/h|H/g, this.getHours());
            str = str.replace(/mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : '0' + this.getMinutes());
            str = str.replace(/m/g, this.getMinutes());
            str = str.replace(/ss|SS/, this.getSeconds() > 9 ? this.getSeconds().toString() : '0' + this.getSeconds());
            str = str.replace(/s|S/g, this.getSeconds());
            return str;
        }

        /*  
        * 比较日期差(原型扩展或重载)  
        * @param {strInterval} 日期类型:'y、m、d、h、n、s、w'  
        * @param {dtEnd} 格式为日期型或者 有效日期格式字符串  
        * @returns 比较结果  
        */
        Date.prototype.dateDiff = function (strInterval, dtEnd) {
            var dtStart = this;
            if (typeof dtEnd == 'string') { //如果是字符串转换为日期型   
                dtEnd = StringToDate(dtEnd);
            }
            switch (strInterval) {
                case 's': return parseInt((dtEnd - dtStart) / 1000);
                case 'n': return parseInt((dtEnd - dtStart) / 60000);
                case 'h': return parseInt((dtEnd - dtStart) / 3600000);
                case 'd': return parseInt((dtEnd - dtStart) / 86400000);
                case 'w': return parseInt((dtEnd - dtStart) / (86400000 * 7));
                case 'm': return (dtEnd.getMonth() + 1) + ((dtEnd.getFullYear() - dtStart.getFullYear()) * 12) - (dtStart.getMonth() + 1);
                case 'y': return dtEnd.getFullYear() - dtStart.getFullYear();
            }
        }

        /* 
        * 日期计算(原型扩展或重载)  
        * @param {strInterval} 日期类型:'y、m、d、h、n、s、w'  
        * @param {Number} 数量  
        * @returns 计算后的日期  
        */
        Date.prototype.dateAdd = function (strInterval, Number) {
            var dtTmp = this;
            switch (strInterval) {
                case 's': return new Date(Date.parse(dtTmp) + (1000 * Number));
                case 'n': return new Date(Date.parse(dtTmp) + (60000 * Number));
                case 'h': return new Date(Date.parse(dtTmp) + (3600000 * Number));
                case 'd': return new Date(Date.parse(dtTmp) + (86400000 * Number));
                case 'w': return new Date(Date.parse(dtTmp) + ((86400000 * 7) * Number));
                case 'q': return new Date(dtTmp.getFullYear(), (dtTmp.getMonth()) + Number * 3, dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
                case 'm': return new Date(dtTmp.getFullYear(), (dtTmp.getMonth()) + Number, dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
                case 'y': return new Date((dtTmp.getFullYear() + Number), dtTmp.getMonth(), dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
            }
        }

        /*  
        * 取得日期数据信息(原型扩展或重载)  
        * @param {interval} 日期类型:'y、m、d、h、n、s、w'  
        * @returns 指定的日期部分  
        */
        Date.prototype.datePart = function (interval) {
            var myDate = this;
            var partStr = '';
            var Week = ['日', '一', '二', '三', '四', '五', '六'];
            switch (interval) {
                case 'y': partStr = myDate.getFullYear(); break;
                case 'm': partStr = myDate.getMonth() + 1; break;
                case 'd': partStr = myDate.getDate(); break;
                case 'w': partStr = Week[myDate.getDay()]; break;
                case 'ww': partStr = myDate.WeekNumOfYear(); break;
                case 'h': partStr = myDate.getHours(); break;
                case 'n': partStr = myDate.getMinutes(); break;
                case 's': partStr = myDate.getSeconds(); break;
            }
            return partStr;
        }

        /*  
        * 字符串包含(原型扩展或重载)  
        * @param {string: str} 要搜索的子字符串  
        * @param {bool: mode} 是否忽略大小写  
        * @returns 匹配的个数  
        */
        String.prototype.matchCount = function (str, mode) {
            return eval("this.match(/(" + str + ")/g" + (mode ? "i" : "") + ").length");
        }

        /*  
        * 去除左右空格(原型扩展或重载)  
        * @type string  
        * @returns 处理后的字符串  
        */
        String.prototype.trim = function () {
            return this.replace(/(^\s*)|(\s*$)/g, "");
        }


        /*  
        * 字符串转换为日期型(原型扩展或重载)  
        * @type Date  
        * @returns 日期  
        */
        String.prototype.toDate = function () {
            var converted = Date.parse(this);
            var myDate = new Date(converted);
            if (isNaN(myDate)) { var arys = this.split('-'); myDate = new Date(arys[0], --arys[1], arys[2]); }
            return myDate;
        }
    </script>
    <script type="text/javascript">
        //测试  
        var a = "{0}--{1}".format("张三", "的歌")  //张三--的歌
        console.log(a);

        var b = "10000".toThousands(2)
        console.log(b); //10,000.00

        var c = "电脑aabbA";
        console.log(c.strLength());  //9

        console.log(c.strStartsWith("电脑")); //true

        console.log(c.checkPassWordLevel()); //2

        var d = [1, 2, 3, 4, 5];
        console.log(d.contains(6)); //-1  不存在
        
        var date = new Date("2016-12-12");
        console.log(date.formatDate("yy-MM")); //16-12

        var date2 = new Date("2016-12-16");
        console.log(date.dateDiff("d", date2)); //4

        console.log(date.dateAdd("y", 2).toLocaleDateString());  //Wed Dec 12 2018

        console.log(date.datePart("d")); //12
        console.log(date.datePart("w")) //一  (星期一)

        console.log(c.matchCount("a", true)); //3

        console.log("   我的  ".trim())  //我的

        console.log("2016 12 12".toDate().toLocaleDateString()) //Mon Dec 12 2016
    </script>


本文转载:CSDN博客