javascript常用知识点集

目录结构

一、jquery源码中常见知识点

二、javascript中原型链常见的知识点

三、常用的方法集知识点

四、经典实例应用

一、jquery源码中常见的知识点

　　1.string，number类型转换的快捷方法

// @param s为字符串，n为数字
function fn(obj){//转换为String类型var s = obj +"";//转换为number类型var n = +obj;
}

　　分享一个面试例子：

//加会将其后面自动转换成字符串
"64"+4="644"
//减会将其自动转换成数字
"64"-4=60

　　2.bool类型转换

　　!!obj，将其强制转换为bool类型

alert(!!0)  //结果为false
alert(!!"33dd")  //结果为true

　　!obj，取相反的bool类型

alert(!0)  //结果为true
alert(!"222333")  //结果为false

　　3.=== 与 ==区别

　　=== 是严格相等，不会进行类型转换，而 == 是不严格相等，会进行类型转换。有些js的书中，建议开发人员永远不要用 == 或者 != 。

　　但是jquery源码中，有用到“==”或者“!=”的情况 —— 判断 undefined 和 null 的时候(undefined == null为true)。

//这里的判断，将obj是null，obj是undefined都排除在外了
if(obj != null){
}

　　4.检测obj是否为window对象

//null == window.null为true
function isWindow(obj){return obj != null && obj == window.obj;
}

　　5.|| 与 && 用法技巧

//例 var aa=5; name = aa || {} ; alert(name) 则name为55
this.name = name || {} //如果name值存在，则值为name，反之为{}//例 var aa=5; name = aa && {} ; alert(name) 则name为{}，因为aa为5，不为0则为真
this.name = bool && [] //如果bool为true，则值为[],反之则为bool

　　经典实例:

( window.foo || ( window.foo = "bar" ) ); alert(window.foo);  //弹出  bar//  为什么最后的结果是bar呢，其实可以看成是   undefined || bar  出来的结果肯定是bar

　　6.setTimeout(fn,0)与setTimeout(fn)区别（此处有问题，没有考虑单线程的问题，请比较了解的大神，帮忙指点）

　　setTimeout(fn,0)与setTimeout(fn)都是延迟执行，但是setTimeout(fn)比setTimeout(fn,0)延迟时间还要长，例

        function fn(){var data = new Date();for(var i=0;i<=1000;i++){if(i==1000){console.log("fn="+data.getTime());}}}function fn1(){var data = new Date();for(var i=0;i<=1000;i++){if(i==1000){console.log("fn1="+data.getTime());}}}setTimeout(fn,0),setTimeout(fn1);

　　结果：

　　7.判断是否为数值

function isNumeric(obj){
return !isNaN(parseFloat(obj)) && isFinite(obj);
}

　　8.判断是否为空对象

function isEmptyObject(){var name;//遍历不是空对象返回for (name in obj) {return false;}return true;
}

　　9.检测对象类型

　　检测obj对象类型，返回类型,通过Object.prototype.toString()来判断类型，但是ie低版本兼容性有问题，因此采用{}.toString来监测，返回为[object Array],[object Object],[object Function]

// 类型判断
function isType(type){return function(o){return Object.prototype.toString.call(o) === '[object ' + type + ']';}
}var isString = isType(“String”);
var isObject = isType("Object");
var isArray = isType("Array");isString("I'm Barret Lee.");
isArray([1,2,3])；
isObject({});

　　10.jquery里的去除空格trim妙用

//相当于if (String.prototype.trim && “\uFEFF\xA0″.trim() !== “”)高级的浏览器已经支持原生的String的trim方法，但是pFan还为了避免它没法解析全角空白，所以加多了一个判断：”\uFEFF\xA0″.trim() !== “”
vart core_version = "1.0",core_trim = core_version.trim;
function trim(){core_trim && !core_trim.call("\uFEFF\xA0") ?function (text) {return text == null ?"" :core_trim.call(text); //这里按我的理解应该为" ".trim.call(text),有点不明白转换为"1.1.0".trim.call(text)
                    } :// 高级的浏览器已经支持原生的String的trim方法，如果浏览器不支持则采用
                    function (text) {var  whitespace = "[\\x20\\t\\r\\n\\f]",rtrim = new RegExp("^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g");return text == null ?"" :(text + "").replace(rtrim, "");},//nodeName函数是获取dom节点的节点名字或者判断其名字跟传入参数是否匹配
                nodeName: function(elem,name){//IE下，DOM节点的nodeName是大写的，例如DIVreturn elem.nodeName && elem.nodeName.toLowerCase() === name.toLowerCase();}
}

　　11.jquery中检测数组或者类数组中是否含存在传入的值

/**检查数组中是否存在传入的值，如果存在就返回值所在的位置，如果不存在就返回-1。*elem 规定需检索的值。*arr 数组*i 可选的整数参数。规定在数组中开始检索的位置。它的合法取值是 0 到 arr.length - 1。如省略该参数，则将从数组首元素开始检索。*/
function inArray(elem, arr, i){var len;if (arr) {//如果浏览器支持Array拥有indexOf方法if ([].indexOf) {return [].indexOf.call(arr, elem, i);}len = arr.length;//当i为负数的时候，从数组后边len+i的位置开始索引//理解这个分成两个部分i = i ? (i < 0 ? Math.max(0, len + i) : i) : 0;，i=i为true，执行(i < 0 ? Math.max(0, len + i) : i)，反正执行i=0i = i ? i < 0 ? Math.max(0, len + i) : i : 0;for (; i < len; i++) {// 双重检测防止类似这样的数组 ar = [];ar[1]=1;ar[0] = undefined; 0 in ar =false;a[0]===undefined; // 0 in arr  => arr[0]是否存在  'nme' in arr => arr['nme']是否存在if (i in arr && arr[i] === elem) {return i;}}}return -1;
}

二、javascript中原型链常见的知识点

　　1.hasOwnProperty()方法

　　使用hasOwnProperty()方法可以检测一个属性是存在与实例，还是存在于原型中。这个方法从Object继承，只在给定属性存在于对象实例中时，才会返回true。

    function Person(){this.age=25;this.job="web";}Person.prototype={name:'pingfan',sayName:function(){alert(this.name);}}var person1=new Person();//来自构造函数，检测属性，也返回truealert(person1.hasOwnProperty("age"));//来自原型属性，返回falsealert(person1.hasOwnProperty("name"));person1.name='ping';//来自实例属性，返回truealert(person1.hasOwnProperty("name"));

　　2.通过instanceOf检查this是否为构造函数的一个实例

 function shiCha(opt){//检测this是否为对象的实例if( !(this instanceof shiCha)){return new shiCha(opt);}
}
var shicha1 = new shiCha(), //会返回一个shiCha对象　　 shicha2 = shiCha(); //构造函数作为函数时与其他函数无意，this指向window

　　3.javascript中Array.prototype.slice.call(arguments)　　

　　我们通常看到Array.prototype.slice.call(arguments,1)或者Array.prototype.slice.call(arguments)，都有点摸不着头脑，其实我们就是借助Array.prototype中slice()将arguments变成一个数组，并且使用该数组工作更方便，第二个参数是从索引值，开始将其变成数组，例Array.prototype.call("22223",2)和Array.prototype.call([1,2,3,4],2)，从字符串第二个开始。

function sliArray(array){//输出为从索引1到索引3return Array.prototype.slice.call(array,1,3);
}
alert(sliArray([1,2,3,4,5,6]))    //结果为2,3

　　4.利用闭包，实现单例模式，保证构造函数只实例一次

//对象之间永远不会完全相等，除非它们是同一对象，因此即使创建一个具有完全相同成员的同类对象，它也不会与第一个对象完全相同          　　　　  var Universe;(function(){var instance;Universe = function Universe(){if(instance){return instance;}instance = this;//所有功能this.start_time = 0;this.bang = "Big";}})()var person1 = new Universe(),person2 = new Universe();alert(person1 === person2 );  //返回true

　　5. 利用空对象F，实现对象继承，效率最高

//利用空对象做媒介，进行继承效果最佳
function inhert(C,P){var F=function(){};F.protototype = P.prototype;C.prototype = new F();C.prototype.constructor = C;
}

　　6. 构造函数设置return obj对象，会导致对象与原型链断掉

　　理解这个问题，先理解一个概念，通常我们用new Object()，其实可以理解为隐式的做了三件事情：

　　　　①.创建一个空对象，var this ={}，继承object对象的一些原有的属性；
　　　　②.将构造函数写的属性挂载到创建的对象，this.name = "pfan";
　　　　③.通过new object()，返回this对象
　　场景一

        var Parent = function (){var that = {};that.name = "pfan"; that.age = "25";return that;}Parent.prototype = {contructor:"Parent",sayName:function(){alert(this.name);},sayAge:function(){alert(this.age);}}    var child = Parent(),last = new Parent();console.dir(child);console.dir(last);child.sayName();last.sayName();

　　我们执行打开chrome控制台，发现通过Parent()，new Parent()方法生成的对象原型链都断裂了。

　　场景二：我们把对象的属性挂载在this上，也达不到想要的结果，构造函数如下：

        var Parent = function (){var that = {};this.name = "pfan"; this.age = "25";return that;}

　　chrome控制台结果：

　　场景三：我们更大胆一点，直接让that成一个对象，返回that，观察new Parent()，出来的对象，是否拥有prototype上的方法

        var Parent = function (){this.name = "pfan"; this.age = "25";var that = {name:"pfan111",age:"2511"}return that;}

　　chrome控制台，可以看到new Parent()，实例返回的对象构造函数设置的返回对象，没有继承原型的prototype方法

　　思考？？：如果构造函数返回Array，null，通过new 实例会出现什么情况呢？

　　1.Array，返回了一个Array对象，无法继承prototype的原型

　　2.null结果是返回继承原型链的对象

　　场景四：构造函数中不返回对象，返回字符串

        var Parent = function (){this.name = "pfan"; this.age = "25";return "11111";}

　　chrome控制台：发现出来的结果，继承了原型链

　　通过以上四个场景，我们得出结论：

　　　　1.构造函数里面，我们设置return 返回对象或者数组，通过new实例时，会导致原型链断裂

　　　　2.构造函数里面，我们设置return 返回字符串或者null，或者alert()，通过new实例时，会直接忽略

三、javascript中常用方法集

　　1. 常见的数组操作方法

　　数组去重：

//数组去重原型
Array.prototype.unqie = function(){ var arr = this, len=this.length, obj={}, newArr=[];            while(len--){ if(obj[ arr[len] ] !== arr[len]){ obj[arr[len]] = arr[len];   newArr.push( arr[len]); }  }
return newArr.reverse();
}//也可以通过变量来记录匹配，效率更高

Array.prototype.unique = function(){
　　var arr = this,poxy,i = arr.length,newArr=[];
　　while(i--){
　　　　if(poxy != arr[i]){
　　　　　　poxy = arr[i];
　　　　　　newArr.push(arr[i]);
　　　　}
　　}
　　return newArr.reverse();
}

　　取数组中最大值：

Array.prototype.arrMax=function(){var arr=this, len=this.length,max=arr[0];for(var i=1;i<len;i++){if(max<arr[i]){max=arr[i];}}return max;
} //数组中通过sort取最大值Array.prototype.arrMax=function(){var arr=this;arr.sort(function(a,b){return a-b;})return arr[arr.length-1];}//利用Math.max取数组最大值
Array.prototype.arrMax =function(){var array = this;return Math.max.apply(null, array);
}
alert([1,2,3,4,5,6,9,8,7,9].arrMax());

　　取数组中最小值：

//数组中最的小值
Array.prototype.arrMin=function(){var arr=this, len=this.length,min=arr[0];for(var i=1;i<len;i++){if(min>arr[i]){min=arr[i];}}return min;
}
//数组中通过sort取最的小值
Array.prototype.arrSortMin=function(){var arr=this;arr.sort(function(a,b){return a-b;})return arr[0];
}//利用Math.max取数组最大值
Array.prototype.arrSortMin =function(){var array = this;return Math.min.apply(null, array);
}
alert([1,2,3,4,5,6,9,8,7,9].arrSortMin());

　　复制数组：

Array.prototype.copy =function() {return [].concat(this);
};

　　去除数组中只指定元素，只能去除一个，如果想多个，之前先用unique处理：

Array.prototype.remove = function(value){for(var i=0,len=this.length;i<len;i++){if(this[i]==value){this.splice(i, 1);break;}}return this;
}

　　判断数组中元素出现的次数最多的一个元素和次数：　

        Array.prototype.maxNum = function(){var arr = this,obj={};for(var i =0, len=arr.length;i<len;i++){var key = arr[i];if( ! obj[key]){obj[key] = 1;}else{obj[key]++;}}var max = -1,maxStr;for( key in obj){if(obj[key]>max){max = obj[key];maxStr = key;}}//alert(maxStr);  maxStr为最大的元素，max为次数return [maxStr,max];}

　　2.操作document.loaction的方法集（这里借用了园友总结的相关方法）

pFan.url = { //#URL//参数：变量名，url为空则表从当前页面的url中取
    getQuery: function (name, url) {var u = arguments[1] || window.location.search, reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)"), r = u.substr(u.indexOf("?") + 1).match(reg);return r != null ? r[2] : "";}, getHash: function (name, url) { //# 获取 hash值var u = arguments[1] || location.hash;var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");var r = u.substr(u.indexOf("#") + 1).match(reg);if (r != null) {return r[2];}return "";}, parse: function (url) { //# 解析URLvar a = document.createElement('a');url = url || document.location.href;a.href = url;return {source: url, protocol: a.protocol.replace(':', ''), host: a.hostname, port: a.port, query: a.search, file: (a.pathname.match(/([^\/?#]+)$/i) || [, ''])[1], hash: a.hash.replace('#', ''), path: a.pathname.replace(/^([^\/])/, '/$1'), relative: (a.href.match(/tps?:\/\/[^\/]+(.+)/) || [, ''])[1], segments: a.pathname.replace(/^\//, '').split('/')
        };}
};

　　3.常用的正则表达式

pFan.regExp = {  //# 字符串匹配//是否为 数字！整数，浮点数isNum: function (num) { //# 是否为数组return !isNaN(num);}, isEmail: function (mail) {//# 是否为 邮箱return /^([a-z0-9]+[_\-\.]?)*[a-z0-9]+@([a-z0-9]+[_\-\.]?)*[a-z0-9]+\.[a-z]{2,5}$/i.test(mail);}, isIdCard: function (card) { //# 是否为 身份证return /^(\d{14}|\d{17})(\d|[xX])$/.test(card);}, isMobile: function (mobile) { //# 是否为 手机return /^0*1\d{10}$/.test(mobile);}, isQQ: function (qq) { //# 是否为 QQreturn /^[1-9]\d{4,10}$/.test(qq);}, isTel: function (tel) { //# 是否为 电话return /^\d{3,4}-\d{7,8}(-\d{1,6})?$/.text(tel);}, isUrl: function (url) { //# 是否为 URLreturn /https?:\/\/[a-z0-9\.\-]{1,255}\.[0-9a-z\-]{1,255}/i.test(url);}, isColor: function (color) { //# 是否为 16进制颜色return /#([\da-f]{3}){1,2}$/i.test(color);}//@id ： 身份证 ，// @now : 当前时间 如：new Date('2013/12/12') , '2013/12/12'// @age ： 允许的年龄, isAdult: function (id, allowAge, now) { //# 是否年龄是否成年var age = 0 // 用户 年月日, nowDate = 0  //当前年月日
        ;allowAge = parseFloat(allowAge) || 18;now = typeof now == 'string' ? new Date(now) : (now || new Date());if (!this.isIdCard(id)) {return false;}//15位身份证if (15 == id.length) {age = '19' + id.slice(6, 6);} else {age = id.slice(6, 14);}// 类型转换 整型age = ~~age;nowDate = ~~(Tydic.date.format('YYYYMMDD', now));//比较年龄if (nowDate - age < allowAge * 1e4) {return false;}return true;}//浮点数, isFloat: function (num) { //# 是否为 浮点数return /^(([1-9]\d*)|(\d+\.\d+)|0)$/.test(num);}//正整数, isInt: function (num) { //# 是否为 正整数return /^[1-9]\d*$/.test(num);}//是否全为汉字, isChinese: function (str) { //# 是否全为 汉字return /^([\u4E00-\u9FA5]|[\uFE30-\uFFA0])+$/gi.test(str);}};

　　4.操作className的方法集

PFan.conClass = {hasClass:function(){return ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)')); },addClass:function(){if (!hasClass(ele,cls)) ele.className += " "+cls; },removeClass:function(){if (hasClass(ele,cls)) { var reg = new RegExp('(\\s|^)'+cls+'(\\s|$)'); ele.className=ele.className.replace(reg,' '); }         }
}

　　5.操作字符串方法

pFan.string = { //# 字符串codeHtml: function (content) { //# 转义 HTML 字符return this.replace(content, {'&': "&amp;", '"': "&quot;", "'": ''', '<': "&lt;", '>': "&gt;", ' ': "&nbsp;", '\t': "    ", '(': "(", ')': ")", '*': "*", '+': "+", ',': ",", '-': "-", '.': ".", '/': "/", '?': "?", '\\': "\", '\n': "<br>"});}//重复字符串, repeat: function (word, length, end) { //# 重复字符串end = end || ''; //加在末位length = ~~length;return new Array(length * 1 + 1).join(word) + '' + end;}//增加前缀, addPre: function (pre, word, size) { //# 补齐。如给数字前 加 0pre = pre || '0';size = parseInt(size) || 0;word = String(word || '');var length = Math.max(0, size - word.length);return this.repeat(pre, length, word);}//去除两边空格, trim: function (text) { //# 去除两边空格return (text || '').replace(/^\s+|\s$/, '');}//去除左边空格
    ,ltrim:function(){ return s.replace( /^(\s*|　*)/, ""); }//去除右边空格
    ,rtrim:function(){ return s.replace( /(\s*|　*)$/, ""); }//返回脚本内容
    ,evalscript:function(s) {if(s.indexOf('<script') == -1) return s;var p = /<script[^\>]*?>([^\x00]*?)<\/script>/ig;var arr = [];while(arr = p.exec(s)) {var p1 = /<script[^\>]*?src=\"([^\>]*?)\"[^\>]*?(reload=\"1\")?(?:charset=\"([\w\-]+?)\")?><\/script>/i;var arr1 = [];arr1 = p1.exec(arr[0]);if(arr1) {appendscript(arr1[1], '', arr1[2], arr1[3]);} else {p1 = /<script(.*?)>([^\x00]+?)<\/script>/i;arr1 = p1.exec(arr[0]);appendscript('', arr1[2], arr1[1].indexOf('reload=') != -1);}}return s;}//清除脚本内容
    ,stripscript:function(){return s.replace(/<script.*?>.*?<\/script>/ig, '');}//字符串替换, replace: function (str, re) { //# 字符串替换str = str || '';for (var key in re) {replace(key, re[key]);};function replace(a, b) {var arr = str.split(a);str = arr.join(b);};return str;}, xss: function (str, type) { //# XSS 转义//空过滤if (!str) {return str === 0 ? "0" : "";}switch (type) {case "html": //过滤html字符串中的XSSreturn str.replace(/[&'"<>\/\\\-\x00-\x09\x0b-\x0c\x1f\x80-\xff]/g, function (r) {return "&#" + r.charCodeAt(0) + ";"}).replace(/ /g, "&nbsp;").replace(/\r\n/g, "<br />").replace(/\n/g, "<br />").replace(/\r/g, "<br />");break;case "htmlEp": //过滤DOM节点属性中的XSSreturn str.replace(/[&'"<>\/\\\-\x00-\x1f\x80-\xff]/g, function (r) {return "&#" + r.charCodeAt(0) + ";"});break;case "url": //过滤urlreturn escape(str).replace(/\+/g, "%2B");break;case "miniUrl":return str.replace(/%/g, "%25");break;case "script":return str.replace(/[\\"']/g, function (r) {return "\\" + r;}).replace(/%/g, "\\x25").replace(/\n/g, "\\n").replace(/\r/g, "\\r").replace(/\x01/g, "\\x01");break;case "reg":return str.replace(/[\\\^\$\*\+\?\{\}\.\(\)\[\]]/g, function (a) {return "\\" + a;});break;default:return escape(str).replace(/[&'"<>\/\\\-\x00-\x09\x0b-\x0c\x1f\x80-\xff]/g, function (r) {return "&#" + r.charCodeAt(0) + ";"}).replace(/ /g, "&nbsp;").replace(/\r\n/g, "<br />").replace(/\n/g, "<br />").replace(/\r/g, "<br />");break;}}// badword , 过滤敏感词//@text : 要过滤的文本 , 类型 ：字符串//@words : 敏感词 ，类型，数组, 如 ： ['你妹', '我丢' ,'我靠']// 如果 用 正则匹配， text 长度 100万，words 100万，需要 4秒！, badWord: function (text, words) { //# 敏感词过滤text = String(text || '');words = words || [];var reg = new RegExp(words.join('|'), 'g'), _self = this;return text.replace(reg, function ($0) {var length = String($0 || '').length;return _self.repeat('*', length);});}};

　　6.加密方法集

pFan.encrypt = { //# 加密md5: function (words) {  //# md5 哈希算法/** Crypto-JS 3.1.2* http://code.google.com/p/crypto-js*/var CryptoJS = function (s, p) {var m = {}, l = m.lib = {}, n = function () { }, r = l.Base = { extend: function (b) { n.prototype = this; var h = new n; b && h.mixIn(b); h.hasOwnProperty("init") || (h.init = function () { h.$super.init.apply(this, arguments) }); h.init.prototype = h; h.$super = this; return h }, create: function () { var b = this.extend(); b.init.apply(b, arguments); return b }, init: function () { }, mixIn: function (b) { for (var h in b) b.hasOwnProperty(h) && (this[h] = b[h]); b.hasOwnProperty("toString") && (this.toString = b.toString) }, clone: function () { return this.init.prototype.extend(this) } }, q = l.WordArray = r.extend({ init: function (b, h) { b = this.words = b || []; this.sigBytes = h != p ? h : 4 * b.length }, toString: function (b) { return (b || t).stringify(this) }, concat: function (b) { var h = this.words, a = b.words, j = this.sigBytes; b = b.sigBytes; this.clamp(); if (j % 4) for (var g = 0; g < b; g++) h[j + g >>> 2] |= (a[g >>> 2] >>> 24 - 8 * (g % 4) & 255) << 24 - 8 * ((j + g) % 4); else if (65535 < a.length) for (g = 0; g < b; g += 4) h[j + g >>> 2] = a[g >>> 2]; else h.push.apply(h, a); this.sigBytes += b; return this }, clamp: function () { var b = this.words, h = this.sigBytes; b[h >>> 2] &= 4294967295 << 32 - 8 * (h % 4); b.length = s.ceil(h / 4) }, clone: function () { var b = r.clone.call(this); b.words = this.words.slice(0); return b }, random: function (b) { for (var h = [], a = 0; a < b; a += 4) h.push(4294967296 * s.random() | 0); return new q.init(h, b) } }), v = m.enc = {}, t = v.Hex = { stringify: function (b) { var a = b.words; b = b.sigBytes; for (var g = [], j = 0; j < b; j++) { var k = a[j >>> 2] >>> 24 - 8 * (j % 4) & 255; g.push((k >>> 4).toString(16)); g.push((k & 15).toString(16)) } return g.join("") }, parse: function (b) { for (var a = b.length, g = [], j = 0; j < a; j += 2) g[j >>> 3] |= parseInt(b.substr(j, 2), 16) << 24 - 4 * (j % 8); return new q.init(g, a / 2) } }, a = v.Latin1 = { stringify: function (b) { var a = b.words; b = b.sigBytes; for (var g = [], j = 0; j < b; j++) g.push(String.fromCharCode(a[j >>> 2] >>> 24 - 8 * (j % 4) & 255)); return g.join("") }, parse: function (b) { for (var a = b.length, g = [], j = 0; j < a; j++) g[j >>> 2] |= (b.charCodeAt(j) & 255) << 24 - 8 * (j % 4); return new q.init(g, a) } }, u = v.Utf8 = { stringify: function (b) { try { return decodeURIComponent(escape(a.stringify(b))) } catch (g) { throw Error("Malformed UTF-8 data"); } }, parse: function (b) { return a.parse(unescape(encodeURIComponent(b))) } },g = l.BufferedBlockAlgorithm = r.extend({ reset: function () { this._data = new q.init; this._nDataBytes = 0 }, _append: function (b) { "string" == typeof b && (b = u.parse(b)); this._data.concat(b); this._nDataBytes += b.sigBytes }, _process: function (b) { var a = this._data, g = a.words, j = a.sigBytes, k = this.blockSize, m = j / (4 * k), m = b ? s.ceil(m) : s.max((m | 0) - this._minBufferSize, 0); b = m * k; j = s.min(4 * b, j); if (b) { for (var l = 0; l < b; l += k) this._doProcessBlock(g, l); l = g.splice(0, b); a.sigBytes -= j } return new q.init(l, j) }, clone: function () { var b = r.clone.call(this); b._data = this._data.clone(); return b }, _minBufferSize: 0 }); l.Hasher = g.extend({ cfg: r.extend(), init: function (b) { this.cfg = this.cfg.extend(b); this.reset() }, reset: function () { g.reset.call(this); this._doReset() }, update: function (b) { this._append(b); this._process(); return this }, finalize: function (b) { b && this._append(b); return this._doFinalize() }, blockSize: 16, _createHelper: function (b) { return function (a, g) { return (new b.init(g)).finalize(a) } }, _createHmacHelper: function (b) { return function (a, g) { return (new k.HMAC.init(b, g)).finalize(a) } } }); var k = m.algo = {}; return m}(Math);(function (s) {function p(a, k, b, h, l, j, m) { a = a + (k & b | ~k & h) + l + m; return (a << j | a >>> 32 - j) + k } function m(a, k, b, h, l, j, m) { a = a + (k & h | b & ~h) + l + m; return (a << j | a >>> 32 - j) + k } function l(a, k, b, h, l, j, m) { a = a + (k ^ b ^ h) + l + m; return (a << j | a >>> 32 - j) + k } function n(a, k, b, h, l, j, m) { a = a + (b ^ (k | ~h)) + l + m; return (a << j | a >>> 32 - j) + k } for (var r = CryptoJS, q = r.lib, v = q.WordArray, t = q.Hasher, q = r.algo, a = [], u = 0; 64 > u; u++) a[u] = 4294967296 * s.abs(s.sin(u + 1)) | 0; q = q.MD5 = t.extend({_doReset: function () { this._hash = new v.init([1732584193, 4023233417, 2562383102, 271733878]) }, _doProcessBlock: function (g, k) {for (var b = 0; 16 > b; b++) { var h = k + b, w = g[h]; g[h] = (w << 8 | w >>> 24) & 16711935 | (w << 24 | w >>> 8) & 4278255360 } var b = this._hash.words, h = g[k + 0], w = g[k + 1], j = g[k + 2], q = g[k + 3], r = g[k + 4], s = g[k + 5], t = g[k + 6], u = g[k + 7], v = g[k + 8], x = g[k + 9], y = g[k + 10], z = g[k + 11], A = g[k + 12], B = g[k + 13], C = g[k + 14], D = g[k + 15], c = b[0], d = b[1], e = b[2], f = b[3], c = p(c, d, e, f, h, 7, a[0]), f = p(f, c, d, e, w, 12, a[1]), e = p(e, f, c, d, j, 17, a[2]), d = p(d, e, f, c, q, 22, a[3]), c = p(c, d, e, f, r, 7, a[4]), f = p(f, c, d, e, s, 12, a[5]), e = p(e, f, c, d, t, 17, a[6]), d = p(d, e, f, c, u, 22, a[7]), c = p(c, d, e, f, v, 7, a[8]), f = p(f, c, d, e, x, 12, a[9]), e = p(e, f, c, d, y, 17, a[10]), d = p(d, e, f, c, z, 22, a[11]), c = p(c, d, e, f, A, 7, a[12]), f = p(f, c, d, e, B, 12, a[13]), e = p(e, f, c, d, C, 17, a[14]), d = p(d, e, f, c, D, 22, a[15]), c = m(c, d, e, f, w, 5, a[16]), f = m(f, c, d, e, t, 9, a[17]), e = m(e, f, c, d, z, 14, a[18]), d = m(d, e, f, c, h, 20, a[19]), c = m(c, d, e, f, s, 5, a[20]), f = m(f, c, d, e, y, 9, a[21]), e = m(e, f, c, d, D, 14, a[22]), d = m(d, e, f, c, r, 20, a[23]), c = m(c, d, e, f, x, 5, a[24]), f = m(f, c, d, e, C, 9, a[25]), e = m(e, f, c, d, q, 14, a[26]), d = m(d, e, f, c, v, 20, a[27]), c = m(c, d, e, f, B, 5, a[28]), f = m(f, c, d, e, j, 9, a[29]), e = m(e, f, c, d, u, 14, a[30]), d = m(d, e, f, c, A, 20, a[31]), c = l(c, d, e, f, s, 4, a[32]), f = l(f, c, d, e, v, 11, a[33]), e = l(e, f, c, d, z, 16, a[34]), d = l(d, e, f, c, C, 23, a[35]), c = l(c, d, e, f, w, 4, a[36]), f = l(f, c, d, e, r, 11, a[37]), e = l(e, f, c, d, u, 16, a[38]), d = l(d, e, f, c, y, 23, a[39]), c = l(c, d, e, f, B, 4, a[40]), f = l(f, c, d, e, h, 11, a[41]), e = l(e, f, c, d, q, 16, a[42]), d = l(d, e, f, c, t, 23, a[43]), c = l(c, d, e, f, x, 4, a[44]), f = l(f, c, d, e, A, 11, a[45]), e = l(e, f, c, d, D, 16, a[46]), d = l(d, e, f, c, j, 23, a[47]), c = n(c, d, e, f, h, 6, a[48]), f = n(f, c, d, e, u, 10, a[49]), e = n(e, f, c, d,C, 15, a[50]), d = n(d, e, f, c, s, 21, a[51]), c = n(c, d, e, f, A, 6, a[52]), f = n(f, c, d, e, q, 10, a[53]), e = n(e, f, c, d, y, 15, a[54]), d = n(d, e, f, c, w, 21, a[55]), c = n(c, d, e, f, v, 6, a[56]), f = n(f, c, d, e, D, 10, a[57]), e = n(e, f, c, d, t, 15, a[58]), d = n(d, e, f, c, B, 21, a[59]), c = n(c, d, e, f, r, 6, a[60]), f = n(f, c, d, e, z, 10, a[61]), e = n(e, f, c, d, j, 15, a[62]), d = n(d, e, f, c, x, 21, a[63]); b[0] = b[0] + c | 0; b[1] = b[1] + d | 0; b[2] = b[2] + e | 0; b[3] = b[3] + f | 0}, _doFinalize: function () { var a = this._data, k = a.words, b = 8 * this._nDataBytes, h = 8 * a.sigBytes; k[h >>> 5] |= 128 << 24 - h % 32; var l = s.floor(b / 4294967296); k[(h + 64 >>> 9 << 4) + 15] = (l << 8 | l >>> 24) & 16711935 | (l << 24 | l >>> 8) & 4278255360; k[(h + 64 >>> 9 << 4) + 14] = (b << 8 | b >>> 24) & 16711935 | (b << 24 | b >>> 8) & 4278255360; a.sigBytes = 4 * (k.length + 1); this._process(); a = this._hash; k = a.words; for (b = 0; 4 > b; b++) h = k[b], k[b] = (h << 8 | h >>> 24) & 16711935 | (h << 24 | h >>> 8) & 4278255360; return a }, clone: function () { var a = t.clone.call(this); a._hash = this._hash.clone(); return a }}); r.MD5 = t._createHelper(q); r.HmacMD5 = t._createHmacHelper(q)})(Math);return CryptoJS.MD5(words).toString();}// sha1, sha1: function (words) { //# sha1  哈希算法var CryptoJS = function (e, m) { var p = {}, j = p.lib = {}, l = function () { }, f = j.Base = { extend: function (a) { l.prototype = this; var c = new l; a && c.mixIn(a); c.hasOwnProperty("init") || (c.init = function () { c.$super.init.apply(this, arguments) }); c.init.prototype = c; c.$super = this; return c }, create: function () { var a = this.extend(); a.init.apply(a, arguments); return a }, init: function () { }, mixIn: function (a) { for (var c in a) a.hasOwnProperty(c) && (this[c] = a[c]); a.hasOwnProperty("toString") && (this.toString = a.toString) }, clone: function () { return this.init.prototype.extend(this) } }, n = j.WordArray = f.extend({ init: function (a, c) { a = this.words = a || []; this.sigBytes = c != m ? c : 4 * a.length }, toString: function (a) { return (a || h).stringify(this) }, concat: function (a) { var c = this.words, q = a.words, d = this.sigBytes; a = a.sigBytes; this.clamp(); if (d % 4) for (var b = 0; b < a; b++) c[d + b >>> 2] |= (q[b >>> 2] >>> 24 - 8 * (b % 4) & 255) << 24 - 8 * ((d + b) % 4); else if (65535 < q.length) for (b = 0; b < a; b += 4) c[d + b >>> 2] = q[b >>> 2]; else c.push.apply(c, q); this.sigBytes += a; return this }, clamp: function () { var a = this.words, c = this.sigBytes; a[c >>> 2] &= 4294967295 << 32 - 8 * (c % 4); a.length = e.ceil(c / 4) }, clone: function () { var a = f.clone.call(this); a.words = this.words.slice(0); return a }, random: function (a) { for (var c = [], b = 0; b < a; b += 4) c.push(4294967296 * e.random() | 0); return new n.init(c, a) } }), b = p.enc = {}, h = b.Hex = { stringify: function (a) { var c = a.words; a = a.sigBytes; for (var b = [], d = 0; d < a; d++) { var f = c[d >>> 2] >>> 24 - 8 * (d % 4) & 255; b.push((f >>> 4).toString(16)); b.push((f & 15).toString(16)) } return b.join("") }, parse: function (a) { for (var c = a.length, b = [], d = 0; d < c; d += 2) b[d >>> 3] |= parseInt(a.substr(d, 2), 16) << 24 - 4 * (d % 8); return new n.init(b, c / 2) } }, g = b.Latin1 = { stringify: function (a) { var c = a.words; a = a.sigBytes; for (var b = [], d = 0; d < a; d++) b.push(String.fromCharCode(c[d >>> 2] >>> 24 - 8 * (d % 4) & 255)); return b.join("") }, parse: function (a) { for (var c = a.length, b = [], d = 0; d < c; d++) b[d >>> 2] |= (a.charCodeAt(d) & 255) << 24 - 8 * (d % 4); return new n.init(b, c) } }, r = b.Utf8 = { stringify: function (a) { try { return decodeURIComponent(escape(g.stringify(a))) } catch (c) { throw Error("Malformed UTF-8 data"); } }, parse: function (a) { return g.parse(unescape(encodeURIComponent(a))) } }, k = j.BufferedBlockAlgorithm = f.extend({ reset: function () { this._data = new n.init; this._nDataBytes = 0 }, _append: function (a) { "string" == typeof a && (a = r.parse(a)); this._data.concat(a); this._nDataBytes += a.sigBytes }, _process: function (a) { var c = this._data, b = c.words, d = c.sigBytes, f = this.blockSize, h = d / (4 * f), h = a ? e.ceil(h) : e.max((h | 0) - this._minBufferSize, 0); a = h * f; d = e.min(4 * a, d); if (a) { for (var g = 0; g < a; g += f) this._doProcessBlock(b, g); g = b.splice(0, a); c.sigBytes -= d } return new n.init(g, d) }, clone: function () { var a = f.clone.call(this); a._data = this._data.clone(); return a }, _minBufferSize: 0 }); j.Hasher = k.extend({ cfg: f.extend(), init: function (a) { this.cfg = this.cfg.extend(a); this.reset() }, reset: function () { k.reset.call(this); this._doReset() }, update: function (a) { this._append(a); this._process(); return this }, finalize: function (a) { a && this._append(a); return this._doFinalize() }, blockSize: 16, _createHelper: function (a) { return function (c, b) { return (new a.init(b)).finalize(c) } }, _createHmacHelper: function (a) { return function (b, f) { return (new s.HMAC.init(a, f)).finalize(b) } } }); var s = p.algo = {}; return p }(Math);(function () { var e = CryptoJS, m = e.lib, p = m.WordArray, j = m.Hasher, l = [], m = e.algo.SHA1 = j.extend({ _doReset: function () { this._hash = new p.init([1732584193, 4023233417, 2562383102, 271733878, 3285377520]) }, _doProcessBlock: function (f, n) { for (var b = this._hash.words, h = b[0], g = b[1], e = b[2], k = b[3], j = b[4], a = 0; 80 > a; a++) { if (16 > a) l[a] = f[n + a] | 0; else { var c = l[a - 3] ^ l[a - 8] ^ l[a - 14] ^ l[a - 16]; l[a] = c << 1 | c >>> 31 } c = (h << 5 | h >>> 27) + j + l[a]; c = 20 > a ? c + ((g & e | ~g & k) + 1518500249) : 40 > a ? c + ((g ^ e ^ k) + 1859775393) : 60 > a ? c + ((g & e | g & k | e & k) - 1894007588) : c + ((g ^ e ^ k) - 899497514); j = k; k = e; e = g << 30 | g >>> 2; g = h; h = c } b[0] = b[0] + h | 0; b[1] = b[1] + g | 0; b[2] = b[2] + e | 0; b[3] = b[3] + k | 0; b[4] = b[4] + j | 0 }, _doFinalize: function () { var f = this._data, e = f.words, b = 8 * this._nDataBytes, h = 8 * f.sigBytes; e[h >>> 5] |= 128 << 24 - h % 32; e[(h + 64 >>> 9 << 4) + 14] = Math.floor(b / 4294967296); e[(h + 64 >>> 9 << 4) + 15] = b; f.sigBytes = 4 * e.length; this._process(); return this._hash }, clone: function () { var e = j.clone.call(this); e._hash = this._hash.clone(); return e } }); e.SHA1 = j._createHelper(m); e.HmacSHA1 = j._createHmacHelper(m) })();return CryptoJS.SHA1(words).toString();}// time33 哈希, time33: function (words) { //# time33 哈希算法words = words || '';//哈希time33算法for (var i = 0, len = words.length, hash = 5381; i < len; ++i) {hash += (hash << 5) + words.charAt(i).charCodeAt();};return hash & 0x7fffffff;}
}

　　7.日期方法集

pFan.date = { //返回时间戳
    getTimeStamp:function(){var timestamp=new Date().getTime();return timestamp.toString();},//时间戳转为日期格式//@nS为时间戳
    getLocalTime: function(nS) {  return new Date(parseInt(nS) * 1000).toLocaleString().substr(0,17);},//@time , 时间 , 如 new Date('2013/11/10 0:12:12')//@pre ， 星期的 前缀，如：周 ，星期//@ nums ，如：一二三四五六日getWeek: function (time, pre, nums) { //# 获取星期几time = typeof time == 'string' ? this.parse(time) : (time || new Date());pre = pre || '星期'; //周nums = nums || '日一二三四五六';return pre + nums[time.getDay()];},//@formatType : YYYY, YY, MM//@ time : new Date('2013/11/12')//@weeks : 日一二三四五六format: function (formatType, time, weeks) { //格式化输出时间var pre = '0',formatType = formatType || 'YYYY-MM-DD',weeks = weeks || '日一二三四五六',time = time || new Date();//格式化时间return (formatType || '').replace(/yyyy|YYYY/g, time.getFullYear()).replace(/yy|YY/g, Tydic.string.addPre(pre, time.getFullYear() % 100), 2).replace(/mm|MM/g, Tydic.string.addPre(pre, time.getMonth() + 1, 2)).replace(/m|M/g, time.getMonth() + 1).replace(/dd|DD/g, Tydic.string.addPre(pre, time.getDate(), 2)).replace(/d|D/g, time.getDate()).replace(/hh|HH/g, Tydic.string.addPre(pre, time.getHours(), 2)).replace(/h|H/g, time.getHours()).replace(/ii|II/g, Tydic.string.addPre(pre, time.getMinutes(), 2)).replace(/i|I/g, time.getMinutes()).replace(/ss|SS/g, Tydic.string.addPre(pre, time.getSeconds(), 2)).replace(/s|S/g, time.getSeconds()).replace(/w/g, time.getDay()).replace(/W/g, weeks[time.getDay()]);}
}

四、经典实例应用

　　1.递归方法实现如下数列：1,1,2,3,5,8,13,21,34,55……

           //a为位数 a为大于1的正整数
           function diGui(a){if(a<=2){return 1;}else{return arguments.callee(a-1)+arguments.callee(a-2);}}alert(diGui(31));

　　2.百度产生时间戳的方法

new Date()/36e5

　　3.获取字符串字节，一个因为字母1个字节，一个中文字符2个字节

        //字节
        function getBite(str){var len = str.length,i=len;while(i--){//中文字符串的charCodeAt码大于255if(strrr[i].charCodeAt()>255)len++;}return len;}alert(getBite(strrr));

　　4.var声明提前的问题

    var  aa = 123;function alaa(){alert(aa)     //结果为undefinedvar aa = "111";   //这里的声明被提前的，但是赋值在后alert(aa);    //结果为111
    }alaa();

　　等价于：

var aa;
alert(aa);
aa=111;
alert(aa);

　　5.操作数组的问题

        var arr = [1,2,3,4,5,6];var newArr = arr;arr.splice(0,3);console.log(newArr);  //弹出结果为[4,5,6]

newArr = arr，这一步其实我们像形成一种拷贝的形式，可是到我们去删除arr数组里面的而原始，发现newArr里面的元素也减少了，所以newArr = arr，只是将newArr的数组指针指向了arr，所以操作arr时影响newArr。解决办法：

        var arr = [1,2,3,4,5,6];var newArr = arr.slice(0);arr.splice(0,3),arr.push("111");console.log(arr);   //结果[4,5,6,"111"]console.log(newArr);  //结果 [1,2,3,4,5,6]

　　6.随机打乱数组

function shuffle(array) {return array.sort(function() {return Math.random() - 0.5});
}

　　　　参考文字打乱数组顺序：http://www.cnblogs.com/wayou/p/fisher_yates_shuffle.html

转载于:https://www.cnblogs.com/pingfan1990/p/4309223.html