JS自带函数
concat
将两个或多个字符的文本组合起来，返回一个新的字符串。
var a = "hello";var b = ",world";var c = a.concat(b);alert(c);//c = "hello,world"
indexOf
返回字符串中一个子串第一处出现的索引（从左到右搜索）。如果没有匹配项，返回 -1 。
var index1 = a.indexOf("l");//index1 = 2var index2 = a.indexOf("l",3);//index2 = 3
charAt
返回指定位置的字符。
var get_char = a.charAt(0);//get_char = "h"
lastIndexOf
返回字符串中一个子串最后一处出现的索引（从右到左搜索），如果没有匹配项，返回 -1 。
var index1 = lastIndexOf('l');//index1 = 3var index2 = lastIndexOf('l',2)//index2 = 2
match
检查一个字符串匹配一个正则表达式内容，如果么有匹配返回 null。
var re = new RegExp(/^\w+$/);var is_alpha1 = a.match(re);//is_alpha1 = "hello"var is_alpha2 = b.match(re);//is_alpha2 = null
substring
返回字符串的一个子串，传入参数是起始位置和结束位置。
var sub_string1 = a.substring(1);//sub_string1 = "ello"var sub_string2 = a.substring(1,4);//sub_string2 = "ell"
substr
返回字符串的一个子串，传入参数是起始位置和长度
var sub_string1 = a.substr(1);//sub_string1 = "ello"var sub_string2 = a.substr(1,4);//sub_string2 = "ello"
replace
用来查找匹配一个正则表达式的字符串，然后使用新字符串代替匹配的字符串。
var result1 = a.replace(re,"Hello");//result1 = "Hello"var result2 = b.replace(re,"Hello");//result2 = ",world"
search
执行一个正则表达式匹配查找。如果查找成功，返回字符串中匹配的索引值。否则返回 -1 。
var index1 = a.search(re);//index1 = 0var index2 = b.search(re);//index2 = -1
slice
提取字符串的一部分，并返回一个新字符串（与 substring 相同）。
var sub_string1 = a.slice(1);//sub_string1 = "ello"var sub_string2 = a.slice(1,4);//sub_string2 = "ell"
split
通过将字符串划分成子串，将一个字符串做成一个字符串数组。
var arr1 = a.split("");//arr1 = [h,e,l,l,o]
length
返回字符串的长度，所谓字符串的长度是指其包含的字符的个数。
var len = a.length();//len = 5
toLowerCase
将整个字符串转成小写字母。
var lower_string = a.toLowerCase();//lower_string = "hello"
toUpperCase
将整个字符串转成大写字母。
var upper_string = a.toUpperCase();//upper_string = "HELLO"
字符串函数扩充
String.prototype.LTrim = function(){return this.replace(/(^\s*)/g, "");}
String.prototype.Rtrim = function(){return this.replace(/(\s*$)/g, "");}
String.prototype.Trim = function(){return this.replace(/(^\s*)|(\s*$)/g, "");}
String.prototype.Left = function(len){if(isNaN(len)||len==null){len = this.length;}else{if(parseInt(len)<0||parseInt(len)>this.length){len = this.length;}}return this.substr(0,len);}
String.prototype.Right = function(len){if(isNaN(len)||len==null){len = this.length;}else{if(parseInt(len)<0||parseInt(len)>this.length){len = this.length;}}return this.substring(this.length-len,this.length);}
String.prototype.Mid = function(start,len){return this.substr(start,len);}
String.prototype.InStr = function(str){if(str==null){str = "";}return this.indexOf(str);}
String.prototype.InStrRev = function(str){if(str==null){str = "";}return this.lastIndexOf(str);}
String.prototype.LengthW = function(){return this.replace(/[^\x00-\xff]/g,"**").length;}
String.prototype.isIP = function(){var reSpaceCheck = /^(\d+)\.(\d+)\.(\d+)\.(\d+)$/;if (reSpaceCheck.test(this)){this.match(reSpaceCheck);if (RegExp.$1 <= 255 && RegExp.$1 >= 0&& RegExp.$2 <= 255 && RegExp.$2 >= 0&& RegExp.$3 <= 255 && RegExp.$3 >= 0&& RegExp.$4 <= 255 && RegExp.$4 >= 0){return true; }else{return false;}}else{return false;}}
String.prototype.isLongDate = function(){var r = this.replace(/(^\s*)|(\s*$)/g, "").match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2}) (\d{1,2}):(\d{1,2}):(\d{1,2})$/);if(r==null){return false;}var d = new Date(r[1], r[3]-1,r[4],r[5],r[6],r[7]);return (d.getFullYear()==r[1]&&(d.getMonth()+1)==r[3]&&d.getDate()==r[4]&&d.getHours()==r[5]&&d.getMinutes()==r[6]&&d.getSeconds()==r[7]);}
String.prototype.isShortDate = function(){var r = this.replace(/(^\s*)|(\s*$)/g, "").match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);if(r==null){return false;}var d = new Date(r[1], r[3]-1, r[4]);return (d.getFullYear()==r[1]&&(d.getMonth()+1)==r[3]&&d.getDate()==r[4]);}
String.prototype.isDate = function(){return this.isLongDate()||this.isShortDate();}
String.prototype.isMobile = function(){return /^0{0,1}13[0-9]{9}$/.test(this);}
String.prototype.isEmail = function(){return /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/.test(this);}
String.prototype.isZipCode = function(){return /^[\\d]{6}$/.test(this);}
String.prototype.existChinese = function(){//[\u4E00-\u9FA5]為漢字﹐[\uFE30-\uFFA0]為全角符號return /^[\x00-\xff]*$/.test(this);}
String.prototype.isFileName = function(){return !/[\\\/\*\?\|:"<>]/g.test(this);}
String.prototype.isUrl = function(){return /^http[s]?:\/\/([\w-]+\.)+[\w-]+([\w-./?%&=]*)?$/i.test(this);}
String.prototype.isIDCard = function(){var iSum=0;var info="";var sId = this; var aCity={11:"北京",12:"天津",13:"河北",14:"山西",15:"内蒙古",21:"辽宁",22:"吉林",23:"黑龙 江",31:"上海",32:"江苏",33:"浙江",34:"安徽",35:"福建",36:"江西",37:"山东",41:"河南",42:"湖 北",43:"湖南",44:"广东",45:"广西",46:"海南",50:"重庆",51:"四川",52:"贵州",53:"云南",54:"西藏",61:"陕西",62:"甘肃",63:"青海",64:"宁夏",65:"新疆",71:"台湾",81:"香港",82:"澳门",91:"国外"};if(!/^\d{17}(\d|x)$/i.test(sId)){return false;}sId=sId.replace(/x$/i,"a");//非法地区if(aCity[parseInt(sId.substr(0,2))]==null){return false;}var sBirthday=sId.substr(6,4)+"-"+Number(sId.substr(10,2))+"-"+Number(sId.substr(12,2));var d=new Date(sBirthday.replace(/-/g,"/"))//非法生日if(sBirthday!=(d.getFullYear()+"-"+ (d.getMonth()+1) + "-" + d.getDate())){return false;}for(var i = 17;i>=0;i--){iSum += (Math.pow(2,i) % 11) * parseInt(sId.charAt(17 - i),11);}if(iSum%11!=1){return false;}return true;}
String.prototype.isPhoneCall = function(){return /(^[0-9]{3,4}\-[0-9]{3,8}$)|(^[0-9]{3,8}$)|(^\([0-9]{3,4}\)[0-9]{3,8}$)|(^0{0,1}13[0-9]{9}$)/.test(this);}
String.prototype.isNumeric = function(flag){//验证是否是数字if(isNaN(this)){return false;}switch(flag){case null: //数字case "":return true;case "+": //正数return /(^\+?|^\d?)\d*\.?\d+$/.test(this);case "-": //负数return /^-\d*\.?\d+$/.test(this);case "i": //整数return /(^-?|^\+?|\d)\d+$/.test(this);case "+i": //正整数return /(^\d+$)|(^\+?\d+$)/.test(this); case "-i": //负整数return /^[-]\d+$/.test(this);case "f": //浮点数return /(^-?|^\+?|^\d?)\d*\.\d+$/.test(this);case "+f": //正浮点数return /(^\+?|^\d?)\d*\.\d+$/.test(this); case "-f": //负浮点数return /^[-]\d*\.\d$/.test(this); default: //缺省return true; }}
String.prototype.IsColor = function(){var temp = this;if (temp=="") return true;if (temp.length!=7) return false;return (temp.search(/\#[a-fA-F0-9]{6}/) != -1);}
String.prototype.toCase = function(){var tmp = "";for(var i=0;i<this.length;i++){if(this.charCodeAt(i)>0&&this.charCodeAt(i)<255){tmp += String.fromCharCode(this.charCodeAt(i)+65248);}else{tmp += String.fromCharCode(this.charCodeAt(i));}}return tmp}
String.prototype.toHtmlEncode = function(){var str = this;str=str.replace(/&/g,"&");str=str.replace(/</g,"<");str=str.replace(/>/g,">");str=str.replace(/\'/g,"'");str=str.replace(/\"/g,""");str=str.replace(/\n/g,"<br>");str=str.replace(/\ /g," ");str=str.replace(/\t/g," ");return str;}
String.prototype.toDate = function(){try{return new Date(this.replace(/-/g, "\/"));}catch(e){return null;}}
