Javascript基础
Javascript冒泡排序
原理
Demo
function score(arr){
for(var i=0;i<arr.length-1;i++){
for(var j=0;j<arr.length-i-1;j++){
if(arr[j]>arr[j+1]){
var temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
}
return arr;
}
console.log(score([2,1,5,4]));
Javascript对象
创建
var obj = {
username:"hongjichao",
age:18,
sayHi:function(){
console.log("hi");
}
}
obj.username;
obj[username];
obj.sayHi();
var obj1 = new Object();
obj1.username = "hongjichao";
obj1.age=18;
obj1.sayHi=function(){
console.log("hi");
}
obj1.username;
obj1[username];
obj1.sayHi();
function Obj2(name,age,sex){
this.name = name;
this.age = age;
this.sex = sex;
this.sing = function(){
console.log("changge");
}
}
var hongjichao = new Obj2("hongjichao",18,"男");
console.log(hongjichao.name);
console.log(hongjichao.sex);
hongjichao.sing();
for (var k in hongjichao){
console.log(k);
console.log(hongjichao[k]);
}
内置对象
数学对象
Math.floor();
Math.ceil();
Math.random();
日期对象
var date = new date();
console.log(date);
date.getFullYear();
date.getMonth();
date.getDate();
date.getDay();
date.getHours();
date.getMinutes();
date.getSeconds();
var arr = ["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
arr[date.getDay()];
date.valueOf();
var times = +new Date();
console.log(Date.now());
d = parseInt(Date.now()/1000/60/60/24);
h = parseInt(Date.now()/1000/60/60%24);
m = parseInt(Date.now()/1000/60%60);
s = parseInt(Date.now()/1000%60);
数组对象
var arr = [];
var arr = new Array();
var arr1 = new Array();
var arr2 = new Array(2,3);
instanceof
console.log(arr instanceof Array);
Array.isArray("参数")
push()
unshift();
pop();
shift();
var arr = [1,2,3];
arr.push(4,"hhh");
var arr = [6,4,98,2,8,10];
var newarr = [];
for(var i=0;i<arr.length;i++){
if(arr[i]<8){
newarr.push(arr[i]);
}
}
console.log(newarr);
reverse();
var arr = [1,2,3];
arr.reverse();
sort();
var arr = [7,5,9,2];
arr.sort(function(a,b){
return a-b;
return b-a;
});
indexOf();
var arr = ["red","blue","purple"];
arr.indexOf("blue");
lastIndexOf();
toString();
join("分割符");
var arr = [1,2,3];
arr.toString();
arr.join("-");
concat();
slice("参数1","参数2");
splice("第几个开始","要删除的个数");
数组去重
function unique(arr){
var newarr = [];
for(var i=0;i<arr.length;i++){
if(newarr.indexOf(arr[i])){
newarr.push(arr[i]);
}
}
return newarr;
}
var demo = unique(["p","u","r","p","l","e"]);
console.log(demo);
字符串对象
arr.toString();
str.charAt(index);
str.charCodeAt(index);
str[index];
var arr = "hong";
var arr = new String("hong");
str.concat(str1,str2....);
str.substr(start,length);
str.slice(start,end);
str.substring(start,end)
str.replace("a","b");
str.split("分割符");
str.toUpperCase();
str.toLowerCase();
简单类型与复杂类型
- 简单数据类型:值类型 string、number、boolean、underfined
- 简单数据类型:null 用typeof null 返回一个空对象object
- 复杂数据类型:引用类型