1、输入一个值,返回其数据类型**

function type(para) {
return Object.prototype.toString.call(para)
}


2、数组去重

function unique1(arr) {
return [...new Set(arr)]
}

function unique2(arr) {
var obj = {};
return arr.filter(ele => {
if (!obj[ele]) {
obj[ele] = true;
return true;
}
})
}

function unique3(arr) {
var result = [];
arr.forEach(ele => {
if (result.indexOf(ele) == -1) {
result.push(ele)
}
})
return result;
}


3、字符串去重

String.prototype.unique = function () {
var obj = {},
str = '',
len = this.length;
for (var i = 0; i < len; i++) {
if (!obj[this[i]]) {
str += this[i];
obj[this[i]] = true;
}
}
return str;
}

###### //去除连续的字符串
function uniq(str) {
return str.replace(/(\w)\1+/g, '$1')
}


4、深拷贝 浅拷贝

//深克隆(深克隆不考虑函数)
function deepClone(obj, result) {
var result = result || {};
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) {
if (typeof obj[prop] == 'object' && obj[prop] !== null) {
// 引用值(obj/array)且不为null
if (Object.prototype.toString.call(obj[prop]) == '[object Object]') {
// 对象
result[prop] = {};
} else {
// 数组
result[prop] = [];
}
deepClone(obj[prop], result[prop])
} else {
// 原始值或func
result[prop] = obj[prop]
}
}
}
return result;
}

// 深浅克隆是针对引用值
function deepClone(target) {
if (typeof (target) !== 'object') {
return target;
}
var result;
if (Object.prototype.toString.call(target) == '[object Array]') {
// 数组
result = []
} else {
// 对象
result = {};
}
for (var prop in target) {
if (target.hasOwnProperty(prop)) {
result[prop] = deepClone(target[prop])
}
}
return result;
}
// 无法复制函数
var o1 = jsON.parse(jsON.stringify(obj1));


5、reverse底层原理和扩展


// 改变原数组
Array.prototype.myReverse = function () {
var len = this.length;
for (var i = 0; i < len; i++) {
var temp = this[i];
this[i] = this[len - 1 - i];
this[len - 1 - i] = temp;
}
return this;
}


6、圣杯模式的继承

function inherit(Target, Origin) {
function F() {};
F.prototype = Origin.prototype;
Target.prototype = new F();
Target.prototype.constructor = Target;
// 最终的原型指向
Target.prop.uber = Origin.prototype;
}


7、找出字符串中第一次只出现一次的字母

String.prototype.firstAppear = function () {
var obj = {},
len = this.length;
for (var i = 0; i < len; i++) {
if (obj[this[i]]) {
obj[this[i]]++;
} else {
obj[this[i]] = 1;
}
}
for (var prop in obj) {
if (obj[prop] == 1) {
return prop;
}
}
}


8、找元素的第n级父元素

function parents(ele, n) {
while (ele && n) {
ele = ele.parentElement ? ele.parentElement : ele.parentNode;
n--;
}
return ele;
}


9、 返回元素的第n个兄弟节点

function retSibling(e, n) {
while (e && n) {
if (n > 0) {
if (e.nextElementSibling) {
e = e.nextElementSibling;
} else {
for (e = e.nextSibling; e && e.nodeType !== 1; e = e.nextSibling);
}
n--;
} else {
if (e.previousElementSibling) {
e = e.previousElementSibling;
} else {
for (e = e.previousElementSibling; e && e.nodeType !== 1; e = e.previousElementSibling);
}
n++;
}
}
return e;
}


10、封装mychildren,解决浏览器的兼容问题


function myChildren(e) {
var children = e.childNodes,
arr = [],
len = children.length;
for (var i = 0; i < len; i++) {
if (children[i].nodeType === 1) {
arr.push(children[i])
}
}
return arr;
}


11、判断元素有没有子元素

function hasChildren(e) {
var children = e.childNodes,
len = children.length;
for (var i = 0; i < len; i++) {
if (children[i].nodeType === 1) {
return true;
}
}
return false;
}


12、我一个元素插入到另一个元素的后面


Element.prototype.insertAfter = function (target, elen) {
var nextElen = elen.nextElenmentSibling;
if (nextElen == null) {
this.appendChild(target);
} else {
this.insertBefore(target, nextElen);
}
}


13、返回当前的时间(年月日时分秒)

function getDateTime() {
var date = new Date(),
year = date.getFullYear(),
month = date.getMonth() + 1,
day = date.getDate(),
hour = date.getHours() + 1,
minute = date.getMinutes(),
second = date.getSeconds();
month = checkTime(month);
day = checkTime(day);
hour = checkTime(hour);
minute = checkTime(minute);
second = checkTime(second);
function checkTime(i) {
if (i < 10) {
i = "0" + i;
}
return i;
}
return "" + year + "年" + month + "月" + day + "日" + hour + "时" + minute + "分" + second + "秒"
}


14、获得滚动条的滚动距离


function getScrollOffset() {
if (window.pageXOffset) {
return {
x: window.pageXOffset,
y: window.pageYOffset
}
} else {
return {
x: document.body.scrollLeft + document.documentElement.scrollLeft,
y: document.body.scrollTop + document.documentElement.scrollTop
}
}
}


15、获得视口的尺寸

function getViewportOffset() {
if (window.innerWidth) {
return {
w: window.innerWidth,
h: window.innerHeight
}
} else {
// ie8及其以下
if (document.compatMode === "BackCompat") {
// 怪异模式
return {
w: document.body.clientWidth,
h: document.body.clientHeight
}
} else {
// 标准模式
return {
w: document.documentElement.clientWidth,
h: document.documentElement.clientHeight
}
}
}
}


16、获取任一元素的任意属性

function getStyle(elem, prop) {
return window.getComputedStyle ? window.getComputedStyle(elem, null)[prop] : elem.currentStyle[prop]
}


17、绑定事件的兼容代码

function addEvent(elem, type, handle) {
if (elem.addEventListener) { //非ie和非ie9
elem.addEventListener(type, handle, false);
} else if (elem.attachEvent) { //ie6到ie8
elem.attachEvent('on' + type, function () {
handle.call(elem);
})
} else {
elem['on' + type] = handle;
}
}


18、解绑事件

function removeEvent(elem, type, handle) {
if (elem.removeEventListener) { //非ie和非ie9
elem.removeEventListener(type, handle, false);
} else if (elem.detachEvent) { //ie6到ie8
elem.detachEvent('on' + type, handle);
} else {
elem['on' + type] = null;
}
}


19、取消冒泡的兼容代码

function stopBubble(e) {
if (e && e.stopPropagation) {
e.stopPropagation();
} else {
window.event.cancelBubble = true;
}
}

20、检验字符串是否是回文

function isPalina(str) {
if (Object.prototype.toString.call(str) !== '[object String]') {
return false;
}
var len = str.length;
for (var i = 0; i < len / 2; i++) {
if (str[i] != str[len - 1 - i]) {
return false;
}
}
return true;
}