常用的String原型

对于常用的字符串原型的举例

在字符串末尾追加字符串 
String.prototype.append = function (str) {
return this.concat(str);
}

删除指定索引位置的字符，索引无效将不删除任何字符 
String.prototype.deleteCharAt = function (index) {
if (index < 0 || index >= this.length) {
return this.valueOf();
}
else if (index == 0) {
return this.substring(1, this.length);
}
else if (index == this.length - 1) {
return this.substring(0, this.length - 1);
}
else {
return this.substring(0, index) + this.substring(index + 1);
}
}
 删除指定索引区间的字符串 
String.prototype.deleteString = function (start, end) {
if (start == end) {
return this.deleteCharAt(start);
}
else {
if (start > end) {
var temp = start;
start = end;
end = temp;
}
if (start < 0) {
start = 0;
}
if (end > this.length - 1) {
end = this.length - 1;
}
return this.substring(0, start) + this.substring(end +1 , this.length);
}
}
 检查字符串是否以subStr结尾 
String.prototype.endWith = function (subStr) {
if (subStr.length > this.length) {
return false;
}
else {
return (this.lastIndexOf(subStr) == (this.length - subStr.length)) ? true : false;
}
}
 比较两个字符串是否相等，也可以直接用 == 进行比较 
String.prototype.equal = function (str) {
if (this.length != str.length) {
return false;
}
else {
for (var i = 0; i < this.length; i++) {
if (this.charAt(i) != str.charAt(i)) {
return false;
}
}
return true;
}
}
 比较两个字符串是否相等，不区分大小写 
String.prototype.equalIgnoreCase = function (str) {
var temp1 = this.toLowerCase();
var temp2 = str.toLowerCase();
return temp1.equal(temp2);
}
 将指定的字符串插入到指定的位置后面，索引无效将直接追加到字符串的末尾 
String.prototype.insert = function (ofset, subStr) {
if (ofset < 0 || ofset >= this.length - 1) {
return this.append(subStr);
}
return this.substring(0, ofset + 1) + subStr + this.substring(ofset + 1);
}
 判断字符串是否数字串 
String.prototype.isAllNumber = function () {
for (var i = 0; i < this.length; i++) {
if (this.charAt(i) < '0' || this.charAt(i) > '9') {
return false;
}
}
return true;
}
 将字符串反序排列 
String.prototype.reserve = function () {
var temp = "";
for (var i = this.length - 1; i >= 0; i--) {
temp = temp.concat(this.charAt(i));
}
return temp;
}
 将指定的位置的字符设置为另外指定的字符或字符串.索引无效将直接返回不做任何处理 
String.prototype.setCharAt = function (index, subStr) {
if (index < 0 || index > this.length - 1) {
return this.valueOf();
}
return this.substring(0, index) + subStr + this.substring(index+1);
}
 检查字符串是否以subStr开头 
String.prototype.startWith = function (subStr) {
if (subStr.length > this.length) {
return false;
}
return (this.indexOf(subStr) == 0) ? true : false;
}
 计算长度，每个汉字占两个长度，英文字符每个占一个长度 
String.prototype.charLength = function () {
var temp = 0;
for (var i = 0; i < this.length; i++) {
if (this.charCodeAt(i) > 255) {
temp += 2;
}
else {
temp += 1;
}
}
return temp;
}
String.prototype.charLengthReg = function () {
return this.replace(/[^\x00-\xff]/g, "**").length;
}
 去掉首尾空格 
String.prototype.trim = function () {
return this.replace(/(^\s*)|(\s*$)/g, "");
}
 测试是否是数字 
String.prototype.isNumeric = function () {
var tmpFloat = parseFloat(this);
if (isNaN(tmpFloat))
return false;
var tmpLen = this.length - tmpFloat.toString().length;
return tmpFloat + "0".Repeat(tmpLen) == this;
}
 测试是否是整数 
String.prototype.isInt = function () {
if (this == "NaN")
return false;
return this == parseInt(this).toString();
}
 获取N个相同的字符串 
String.prototype.Repeat = function (num) {
var tmpArr = [];
for (var i = 0; i < num; i++) tmpArr.push(this);
return tmpArr.join("");
}
 除去左边空白  
String.prototype.LTrim = function () {
return this.replace(/^s+/g, "");
}
 除去右边空白 
String.prototype.RTrim = function () {
return this.replace(/s+$/g, "");
}
 除去两边空白  
String.prototype.trim = function () {
return this.replace(/(^s+)|(s+$)/g, "");
}
 保留数字 
String.prototype.getNum = function () {
return this.replace(/[^d]/g, "");
}
 保留字母 
String.prototype.getEn = function () {
return this.replace(/[^A-Za-z]/g, "");
}
 保留中文
String.prototype.getCn = function () {
return this.replace(/[^u4e00-u9fa5uf900-ufa2d]/g, "");
}
 得到字节长度 
String.prototype.getRealLength = function () {
return this.replace(/[^x00-xff]/g, "--").length;
}
 从左截取指定长度的字串 
String.prototype.left = function (n) {
return this.slice(0, n);
}
 从右截取指定长度的字串  
String.prototype.right = function (n) {
return this.slice(this.length - n);
}
 删除首尾空格  
String.prototype.Trim = function() {
return this.replace(/(^\s*)|(\s*$)/g, "");
}

统计指定字符出现的次数  
String.prototype.Occurs = function(ch) {
// var re = eval("/[^"+ch+"]/g");
// return this.replace(re, "").length;
return this.split(ch).length-1;
}

检查是否由数字组成 
String.prototype.isDigit = function() {
var s = this.Trim();
return (s.replace(/\d/g, "").length == 0);
}

检查是否由数字字母和下划线组成 
String.prototype.isAlpha = function() {
return (this.replace(/\w/g, "").length == 0);
}

检查是否为数 
String.prototype.isNumber = function() {
var s = this.Trim();
return (s.search(/^[+-]?[0-9.]*$/) >= 0);
}

返回字节数
String.prototype.lenb = function() {
return this.replace(/[^\x00-\xff]/g,"**").length;
}

检查是否包含汉字
String.prototype.isInChinese = function() {
return (this.length != this.replace(/[^\x00-\xff]/g,"**").length);
}

简单的email检查 
String.prototype.isEmail = function() {
　var strr;
var mail = this;
　var re = /(\w+@\w+\.\w+)(\.{0,1}\w*)(\.{0,1}\w*)/i;
　re.exec(mail);
　if(RegExp.$3!="" && RegExp.$3!="." && RegExp.$2!=".")
strr = RegExp.$1+RegExp.$2+RegExp.$3;
　else
　　if(RegExp.$2!="" && RegExp.$2!=".")
strr = RegExp.$1+RegExp.$2;
　　else
　strr = RegExp.$1;
　return (strr==mail);
}

简单的日期检查，成功返回日期对象  
String.prototype.isDate = function() {
var p;
var re1 = /(\d{4})[年./-](\d{1,2})[月./-](\d{1,2})[日]?$/;
var re2 = /(\d{1,2})[月./-](\d{1,2})[日./-](\d{2})[年]?$/;
var re3 = /(\d{1,2})[月./-](\d{1,2})[日./-](\d{4})[年]?$/;
if(re1.test(this)) {
p = re1.exec(this);
return new Date(p[1],p[2],p[3]);
}
if(re2.test(this)) {
p = re2.exec(this);
return new Date(p[3],p[1],p[2]);
}
if(re3.test(this)) {
p = re3.exec(this);
return new Date(p[3],p[1],p[2]);
}
return false;
}

检查是否有列表中的字符字符
String.prototype.isInList = function(list) {
var re = eval("/["+list+"]/");
return re.test(this);
}

系统中JS的扩展函数

/清除两边的空格
String.prototype.trim = function() {
return this.replace(/(^\s*)|(\s*$)/g, '');
};
 合并多个空白为一个空白
String.prototype.ResetBlank = function() {
var regEx = /\s+/g;
return this.replace(regEx, ' ');
};

保留数字
String.prototype.GetNum = function() {
var regEx = /[^\d]/g;
return this.replace(regEx, '');
};

保留中文
String.prototype.GetCN = function() {
var regEx = /[^\u4e00-\u9fa5\uf900-\ufa2d]/g;
return this.replace(regEx, '');
};

String转化为Number
String.prototype.ToInt = function() {
return isNaN(parseInt(this)) ? this.toString() : parseInt(this);
};

得到字节长度
String.prototype.GetLen = function() {
var regEx = /^[\u4e00-\u9fa5\uf900-\ufa2d]+$/;
if (regEx.test(this)) {
return this.length * 2;
} else {
var oMatches = this.match(/[\x00-\xff]/g);
var oLength = this.length * 2 - oMatches.length;
return oLength;
}
};

获取文件全名
String.prototype.GetFileName = function() {
var regEx = /^.*\/([^\/\?]*).*$/;
return this.replace(regEx, '$1');
};

数字补零
Number.prototype.LenWithZero = function(oCount) {
var strText = this.toString();
while (strText.length < oCount) {
strText = '0' + strText;
}
return strText;
};

Unicode还原
Number.prototype.ChrW = function() {
return String.fromCharCode(this);
};

数字数组由小到大排序
Array.prototype.Min2Max = function() {
var oValue;
for (var i = 0; i < this.length; i++) {
for (var j = 0; j <= i; j++) {
if (this[i] < this[j]) {
oValue = this[i];
this[i] = this[j];
this[j] = oValue;
}
}
}
return this;
};

数字数组由大到小排序
Array.prototype.Max2Min = function() {
var oValue;
for (var i = 0; i < this.length; i++) {
for (var j = 0; j <= i; j++) {
if (this[i] > this[j]) {
oValue = this[i];
this[i] = this[j];
this[j] = oValue;
}
}
}
return this;
};

获得数字数组中最大项
Array.prototype.GetMax = function() {
var oValue = 0;
for (var i = 0; i < this.length; i++) {
if (this[i] > oValue) {
oValue = this[i];
}
}
return oValue;
};

获得数字数组中最小项
Array.prototype.GetMin = function() {
var oValue = 0;
for (var i = 0; i < this.length; i++) {
if (this[i] < oValue) {
oValue = this[i];
}
}
return oValue;
};

获取当前时间的中文形式
Date.prototype.GetCNDate = function() {
var oDateText = '';
oDateText += this.getFullYear().LenWithZero(4) + new Number(24180).ChrW();
oDateText += this.getMonth().LenWithZero(2) + new Number(26376).ChrW();
oDateText += this.getDate().LenWithZero(2) + new Number(26085).ChrW();
oDateText += this.getHours().LenWithZero(2) + new Number(26102).ChrW();
oDateText += this.getMinutes().LenWithZero(2) + new Number(20998).ChrW();
oDateText += this.getSeconds().LenWithZero(2) + new Number(31186).ChrW();
oDateText += new Number(32).ChrW() + new Number(32).ChrW() + new Number(26143).ChrW() + new Number(26399).ChrW() + new String('26085199682010819977222352011620845').substr(this.getDay() * 5, 5).ToInt().ChrW();
return oDateText;
};
扩展Date格式化
Date.prototype.Format = function(format) {
var o = {
"M+": this.getMonth() + 1, //月份
"d+": this.getDate(), //日
"h+": this.getHours() % 12 == 0 ? 12 : this.getHours() % 12, //小时
"H+": this.getHours(), //小时
"m+": this.getMinutes(), //分
"s+": this.getSeconds(), //秒
"q+": Math.floor((this.getMonth() + 3) / 3), //季度
"S": this.getMilliseconds() //毫秒
};
var week = {
"0": "\u65e5",
"1": "\u4e00",
"2": "\u4e8c",
"3": "\u4e09",
"4": "\u56db",
"5": "\u4e94",
"6": "\u516d"
};
if (/(y+)/.test(format)) {
format = format.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
}
if (/(E+)/.test(format)) {
format = format.replace(RegExp.$1, ((RegExp.$1.length > 1) ? (RegExp.$1.length > 2 ? "\u661f\u671f" : "\u5468") : "") + week[this.getDay() + ""]);
}
for (var k in o) {
if (new RegExp("(" + k + ")").test(format)) {
format = format.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
}
}
return format;
}
Date.prototype.Diff = function(interval, objDate) {
 若参数不足或 objDate 不是日期类型則回传 undefined
if (arguments.length < 2 || objDate.constructor != Date) { return undefined; }
switch (interval) {
//计算秒差
case 's': return parseInt((objDate - this) / 1000);
//计算分差
case 'n': return parseInt((objDate - this) / 60000);
//计算時差
case 'h': return parseInt((objDate - this) / 3600000);
//计算日差
case 'd': return parseInt((objDate - this) / 86400000);
//计算周差
case 'w': return parseInt((objDate - this) / (86400000 * 7));
//计算月差
case 'm': return (objDate.getMonth() + 1) + ((objDate.getFullYear() - this.getFullYear()) * 12) - (this.getMonth() + 1);
//计算年差
case 'y': return objDate.getFullYear() - this.getFullYear();
//输入有误
default: return undefined;
}
};

检测是否为空
Object.prototype.IsNullOrEmpty = function() {
var obj = this;
var flag = false;
if (obj == null || obj == undefined || typeof (obj) == 'undefined' || obj == '') {
flag = true;
} else if (typeof (obj) == 'string') {
obj = obj.trim();
if (obj == '') {//为空
flag = true;
} else {//不为空
obj = obj.toUpperCase();
if (obj == 'NULL' || obj == 'UNDEFINED' || obj == '{}') {
flag = true;
}
}
}
else {
flag = false;
}
return flag;
};