一些常用的JS方法
//數組去重
Array.prototype.myUnique = function unique() {
var obj = {};
for (var i = 0; i < this.length; i++) {
var cur = this[i];
if (obj[cur] == cur) {
this[i] = this[this.length - 1];
this.length--;
i--;
continue;
}
obj[cur] = cur;
}
obj = null;
return this;
}
//冒泡排序
function bubbleSort(ary) {
var temp = null;
for (var i = 0; i < ary.length - 1; i++) {//i轮数
for (var j = 0; ary.length - 1 - i; j++) {
if(ary[j] > ary[j+1]){
temp = ary[j];
ary[j] = ary[j+1];
ary[j+1] = temp;
}
}
}
return ary;
}
//快速排序
function quickSort(ary) {
if (ary.length<=1){
return ary;
}
var pointIndex = Math.floor(ary.length/2);//向下取整
var pointValue = ary.splice(pointIndex,1)[0];//删除一个pointIndex的1项 原有数组
var left=[];
var right=[];
for(var i=0;i=0;){
if(cur max ? max = cur : null;
cur < min ? min = cur : null;
}
//3 Math方法 必须一个一个传 Math又是一个function,所以可以用apply方法
var max = Math.max.apply(null, ary);
var min = Math.min.apply(null, ary);
console.log(max);
//ES6
Math.max.apply[...ary]
Math.min.apply[...ary]
//4 字符串拼接 用eval变成js表达式
var nax = eval("Math.max(" + ary.toString() + ")");
//数组的平均数
function avgFn() {
var ary = [];
for (var i = 0; i < arguments.length; i++) {
ary[ary.length] = arguments[i];
}
ary.sort(function (a, b) {
return a - b;
});
ary.shift(); //移除首位
ary.pop(); //移除末尾
return eval(ary.join("+")) / ary.length.toFixed(2);
}
//获取随机数n-m的随机数
function getRandom(n, m) {
n = Number(n);
m = Number(m);
if (isNaN(n) || isNaN(m)) {
return Math.random();
}
if (n > m) {
var temp = n;
n = m;
m = temp;
}
return Math.round(Math.random() * (m - n) + n);
}
//递归
//从1-10把所有能被2整除的相乘
function fn(n) {
if (n === 1) {
return 1;
}
if (n % 2 !== 0) {
return fn(n - 1);
}
return n * fn(n - 1);
}
//类数组转化 try catch转化不兼容ie问题
//单例模式
var utils = (function () {
var flag = "getComputedStyle" in window;
return {
listToArray: listToArray,
jsonParse: jsonParse,
getCss: getCss,
win: win,
children: children,
prev: prev,
next: next,
sibling: sibling,
firstchild: firstchild,
lastChild: lastChild,
setCss: setCss,
css: css
}
function listToArray(likeAry) {
if (flag) {
return Array.prototype.slice.call(likeAry);
}
var ary = [];
for (i = 0; i < likeAry.length; i++) {
ary[ary.length] = likeAry[i];
}
return ary;
}
,
//JSON 字符串 转JSON对象
function jsonParse(str) {
var val = null;
try {
val = JSON.Parse(str);
} catch (e) {
eval("(" + str + ")");
}
return val;
}
,
//getCss:获取当前元素所有经过浏览器计算过的样式中的attr对应的值
//curEle:[object]当前要操作的元素对象
//attr:[string] 我们要获取的样式属性的名称
function getCss(curEle, attr) {
var val = null,
reg = null;
try {
window.getComputedStyle(curEle, null)[attr];
} catch (e) {
val = curEle.currentStyle[attr];
}
reg = /^(-?\d+(\.\d+)?)(px|pt|em|rem)?$/;
return reg.test(val) ? parseFloat(val) : val;
}
,
//win:获取或者设置了关于浏览器的黑子模型的信息
function win(attr, value) {
//不传value的话默认是获取样式值
if (typeof value === "undefined") {
return document.documentElement[attr] || document.body[attr];
}
document.documentElement[attr] = value;
document.body[attr] = value;
}
,
//获取所有元素子节点或者 TAGNAME下的
function children(curEle, tagName) {
var nodeList = curEle.childNodes;
var ary = [];
if (!flag) {
for (var i = 0; i < nodeList.length; i++) {
var currentNode = nodeList[i];
currentNode.nodeType === 1 ? ary[ary.length] = currentNode : null;
}
nodeList = null;
} else {
ary = [].prototype.slice.call(curEle.children); //类数组转换
}
if (typeof(tagName) === "string") {
for (var k = 0; k < ary.length; k++) {
var curEleNode = ary[k];
if (curEleNode.nodeName.toLowerCase() !== tagName.toLowerCase()) {
ary.splice(k, 1);
k--;
}
}
}
return ary;
}
,
//获取当前元素的哥哥节点,判断是否为元素节点,不是的话给予当前的继续找上面的哥哥节点,一直找哥哥节点,
function prev(curEle) {
try {
return curEle.previousElementSibling;
} catch (e) {
var pre = curEle.previousSibling;
whilep(pre && pre.nodeType !== 1)
{
pre = pre.previousSibling;
}
return pre;
}
}
,
function next(curEle) {
try {
return curEle.nextElementSibling;
} catch (e) {
var next = curEle.nextSibling;
whilep(next && next.nodeType !== 1)
{
next = next.previousSibling;
}
return next;
}
}
,
//获取相邻的
function sibling(curEle) {
var pre = this.prev(curEle);
var next = this.next(curEle);
var ary = [];
pre ? ary.push(pre) : null;
next ? ary.push(next) : null;
return ary;
}
,
//firstchild
function firstchild(curEle) {
var chs = this.children(curEle);
return chs.length > 0 ? chs[0] : null;
}
,
function lastChild(curEle) {
var chs = this.children(curEle);
return chs.length > 0 ? chs[chs.length - 1] : null;
}
,
function setCss(curEle, attr, value) {
var reg = /^(width|height|bottom|top|left|right|((margin|padding)(Top|Bottom|Left|Right)?))$/;
if (reg.test(attr)) {
//判断是否是一个有效数字
if (!isNaN(value)) {
value += "px";
}
}
curEle["style"][attr] = value;
}
,
//css:此方法实现了获取,单独设置,批量设置元素的样式
function css(curEle, options) {
var argTwo = arguments[1];
if (typeof argTwo === "string") {
var argThree = arguments[2];
if (!argThree) {
return this.getCss(curEle, argTwo);
return this.getCss.apply(this, arguments);
}
// this.setCss(curEle,argTwo,argThree);
this.setCss.apply(this, arguments);
return;
}
}
})();
//等同于Jquery的offset方法, 实现页面中任意一个元素,距离body的便宜(包含左偏移和上偏移),不管当前元素的父级参照物是谁
function offset(curEle) {
var totalLef = null,
totalTop = null,
par = curEle.offsetParent;
totalLef += curEle.offsetLeft;
totalTop += curEle.offsetTop;
//只要没有找到BODY,我们就吧父级参照物的边框和偏移量进行累加
while (par) {
//累加父级参照物的边框
totalLef += par.clientLeft;
totalTop += par.clientTop;
//父级参照物本身的偏移
totalLef += par.offsetLeft;
totalTop += par.offsetTop;
par = par.offsetParent;
}
return {
left: totalLef,
top: totalTop
};
}
//回到顶部的效果
function () {
window.onscroll = null;
var duration = 500,
interval = 10,
target = document.documentElement.scrollTop;
var step = traget / duration * interval;
var timer = window.setInterval(function () {
var curTop = document.documentElement.scrollTop;
if (curTop === 0) {
window.clearInterval(timer);
window.onscroll = computed;
return;
}
curTop -= step;
document.documentElement.scrollTop = curTop;
}, 10);
}
//window.onscroll不管怎么操作 就会触发
window.onscroll = function computed() {
var curTop = document.documentElement.scrollTop || document.body.scrollTop;
var curHeight = document.documentElement.clientHeight;
goLink.style.display = curTop > curHeight ? "block" : "none"
}
