笔试部分

2018.3

/**
*龙珠
*/
<p>
        1.doctype的作用?标准模式与兼容模式有什么区别?
        2.行内元素有哪些?块级元素有哪些?空(void)元素有哪些?
        3.html5有哪些新特性,新元素?如何处理html5新标签的浏览器兼容问题?如何区分HTML和HTML5?
        4.描述一下cookie和sessionStorage和localStorage的区别?
        5.webSocket如何兼容低版本浏览器?
        6.介绍一下标准的css的盒子模型?低版本IE的盒模型有什么不同?
        7.css选择符有哪些?哪些属性可以继承?css的权重怎么定义?
        8.用纯css创建一个三角形的原理是什么?
        9.li与li之间看不见的空白间隙是什么原因引起的?有什么解决办法?
        10.什么是css预处理器/后处理器?
        11.JavaScript有几种值类型?
        12.ajax是什么?如何创建一个ajax?同源策略是什么?使用它有什么问题?
        13.什么是闭包,为什么要用他?
        14.json和jsonp分别是什么?
</p>

/** 
 * 龙珠
*/
var arr = [11<12<13 , 13<14<15];

var str = "1 2 3".replace(/\d/g,parseInt);

var bool = ([] == []);

var str1 = '5' + 3;
var str2 = 5 + 3;
var str3 = 5 + "3";

var a = [1,2,3],
    b = [1,2,3],
    c = [1,2,4],
    res1 = (a == b),
    res2 = (a === b),
    res3 = (a > c),
    res4 = (a<c);

var one = 0.1,
    two = 0.2,
    six = 0.6,
    eight = 0.8,
    red1 = two - one == one,
    red2 = eight - six == two;

function show(params) {
    switch (params) {
        case 'A':
            console.log("A");
            break;
        case 'B':
            console.log("B");
            break;
        case undefined:
            console.log("undefined");
            break;
    
        default:
            console.log('idontknow');
            
            break;
    }
    
}
show(String('A'))
show(new String('A'));


var a = [0];
if ([0]) {
    console.log(a == true);
}else{
    console.log("a");
    
}


var arr = Array(3);
arr[0] = 2;
var res = arr.map(function (params) {
    return "1";
})


function f() {
    var a = f.prototype,
        b = Object.getPrototypeOf(f);
        console.log(a);
        console.log(b);       
    console.log(a === b);
    
}
f();


function a(arr) {
    arr[0] = arr[2];
}

function b(c,d,f) {
    f = 10;
    a(arguments);
    return c + d + f;
}

b(1,1,1);

/**
 * 兴业证券
*/

// var a = [];
// var a = {};
// var a = ();
// var a = //;

// 关键字与保留字
// calss  viod  parent with

var a = [1,2];
console.log(a.concat([3,4],[[5,6]]).join(" "));
console.log(a.concat([3, 4], [[5, 6]]).length);


null === undefined;
null == undefined;
null instanceof Object;
NaN == NaN;


function a() {

    try {
        return "try";
    } catch (error) {
        return "err";
    }finally {
        return "finally";
    }

}
a();


var F = function () { };
var P = F.prototype;
var C = P.constructor;
console.log(C === F ,  C == F);
typeof F;


function foo() {

    "use strict";
    return !this;
    
}

function boo() {
    
    return !this;

}
console.log(foo() + " " + boo());



var arr = [];
arr[-1] = -1;
console.log(arr);
console.log(arr.length);
arr[0] = 0;
var len = arr.length;
arr[1024] = 1024;
console.log(arr);
var len1 = arr.length;
console.log(len + " " + len1);


var parent = {r:1};
var c = Object.create(parent);
c.r = 3;
console.log(parent.r + " " + c.r);


function res(x) {
    if (x % 2 === 0) {
        return
        false;
    }
    return true;
}
console.log(res(1) + " " + res(2));



var s = "12345";
s.len = 4;
var t = s.len;
console.log(t);



const greet = [];
for (let i = 0; i < 10; i++) {
    greet.push(function () {
        return console.log(i);
    })
}
greet[0]();
greet[1]();