《JavaScript高级程序设计2》学习笔记——引用类型

//Object类型
    //new操作符创建Object实例
var person = new Object();
person.name = 'chemdemo';
person.age = 23;
    //对象字面量创建对象
var person = {
    name : "chemdemo",
    age : 23
};

var person = {
    "name" : 'chemdemo',
    'age' : 23
};

var person = {};
person.name = 'chemdemo';
person.age = 23;

function displayInfo(args) {
    var output = "";
    if (typeof args.name == "string") {
        output += "Name: " + args.name + '\n';
    }
    if (typeof args.age == "number") {
        output += "Age: " + args.age + '\n';
    }
    alert(output);
}
displayInfo ({
    name : 'chemdemo',
    age : 23
});
displayInfo ({
    name : "Greg"
});

alert(person["name"]);//访问person对象的name属性
alert(person.name);//访问person对象的name属性

var propertyName = "name";
alert(person[propertyName]);//访问person对象的name属性

//Array类型
var colors = new Array();
var colors = new Array(20);//创建包含20个项的数组
var colors = new Array("red", "blue", "yellow");
var colors = Array(20);//创建包含20个项的数组

var colors = ["red", "blue", "yellow"];//创建一个包含3个字符串的数组
var name = [];//创建一个空数组
var values = [1, 2, ];//创建一个包含2或3项的数组（不建议这样）
var options = [,,,,];//创建一个包含4或5项的数组（不建议这样）

var colors = ["red", "blue", "yellow"];
alert(colors[0]);//red
colors[2] = "black";//修改第三项值
colors[3] = "green";//新增第四项

var colors = ["red", "blue", "yellow"];
colors.length = 4;
alert(colors[3]);//undefined

var colors = ["red", "blue", "yellow"];
colors[colors.length] = "black";//（在位置3）添加一种颜色
colors[colors.length] = "brown";//（在位置4）添加一种颜色

//转换方法
var colors = ["red", "blue", "yellow"];
alert(colors.toString());//red,blue,yellow
alert(colors.valueOf());//red,blue,yellow
alert(colors);//red,blue,yellow

var colors = ["red", "blue", "yellow"];
alert(colors.join(","));//red,blue,yellow
alert(colors.join("||"));//red||blue||yellow

//栈方法
var colors = new Array();
var count = colors.push("red", "black");//插入两项
alert(count);//2

count = colors.push("blue");
alert(count);//3

var item = colors.pop();
alert(item);//blue
alert(colors.length);//2

//队列方法
var colors = new Array();
var count = colors.push("red", "black");//插入两项
alert(count);//2

count = colors.push("blue");
alert(count);//3

var item = colors.shift();//取得第一项
alert(item);//red
alert(colors.length);//2

var colors = new Array();
var count = colors.unshift("red", "black");
alert(count);//2

//重排序方法
var values = [1, 2, 3, 4, 5];
values.reverse();
alert(values);//5,4,3,2,1

var values = [0, 1, 5, 10, 15];
values.sort();
alert(values);//0,1,10,15,5

function compare1(value1, value2) {//升序排列
    if(value1 < value2) {
        return -1;
    } else if(value1 > value2) {
        return 1;
    } else {
        return 0;
    }
}
function compare2(value1, value2) {//降序排列
    if(value1 < value2) {
        return 1;
    } else if(value1 > value2) {
        return -1;
    } else {
        return 0;
    }
}
var values = [0, 1, 5, 10, 15];
values.sort(compare1);
alert(values);//0,1,5,10,15
values.sort(compare2);
alert(values);//15,10,5,0

function compare1(value1, value2) {//降序排列
    return value1 - value2;
}
function compare2(value1, value2) {//升序排列
    return value2 - value1;
}

//操作方法
var colors = ["red", "blue", "yellow"];
var colors2 = colors.concat("green", ["black", "brown"]);
alert(colors.length);//3
alert(colors2.length);//6

var colors = ["red", "blue", "yellow", "black", "brown", "green"];
var colors2 = colors.slice(3);
alert(colors2);//black,brown,green
var colors3 = colors.slice(2, 4);
alert(colors2);//yellow,black

var colors = ["red", "blue", "yellow"];
var removed = colors.splice(0, 1);//删除第一项
alert(colors);//blue,yellow
alert(removed);//red

removed = colors.splice(1, 0, "green", "orange");//从位置1开始插入两项
alert(colors);//blue,green,orange,yellow
alert(removed);//空数组

removed = colors.splice(1, 1, "red", "purple");//插入两项，删除一项
alert(colors);//blue,red,purple,orange,yellow
alert(removed);//green

//Date类型
var now = new Date();
var someDate = new Date(Date.parse("May 25, 2008"));
var someDate = new Date("May 25, 2008");

var y2k = new Date(Date.UTC(2000, 0));//GMT时间2000年1月1日午夜零时
var allFives = new Date(Date.UTC(2005, 4, 5, 17, 55, 55));//GMT时间2005年5月5日下午5:55:55

var y2k = new Date(2000, 0);//本地时间2000年1月1日午夜零时
var allFives = new Date(2005, 4, 5, 17, 55, 55);//本地时间2005年5月5日下午5:55:55

var date1 = new Date(2007, 0, 1);//January 1, 2007
var date2 = new Date(2007, 1, 1);//Februzary 1, 2007
alert(date1 < date2);//true


function createComparisionFunction(propertyName) {
    return function(object1, object2) {
        var value1 = object1[propertyName];
        var value2 = object2[propertyName];
        if(object1 < object2) {
            return -1;
        } else if(object1 > object2) {
            return 1;
        } else {
            return 0;
        }
    };
}

var data = [{name : "Zhang", age : 26}, {name : "Huang", age : 24}];
data.sort(createComparisionFunction("name"));
alert(data[0].name);

function factorial(num) {//阶乘函数
    if(num <= 1) {
        return 1;
    } else {
        return num*arguments.callee(num-1);
    }
}
var res = facto'rial(5);
alert(res);

window.color = "red";
var o = {color: "blue"};

function sayColor() {
    alert(this.color);
}

sayColor();//red
o.sayColor = sayColor;
o.sayColor();

function sum(num1, num2) {
    return num1+num2;
}

function callSum1(num1, num2) {
    return sum.apply(this, arguments);
}
alert(callSum1(10, 20));

function callSum2(num1, num2) {
    return sum.apply(this, [num1, num2]);
}
alert(callSum2(10, 20));

var stringValue = "Lorem ipsum dolor sit amet, consecteurt adipisicing elit";
var pos = stringValue.indexOf("e");
var positions = new Array();
while(pos > -1) {
    positions.push(pos);
    pos = stringValue.indexOf("e", pos + 1);
}
alert(positions);

var text = 'cat, bat, sat, fat';
var pattern = /.at/;
var matchs = text.match(pattern);
alert(matchs.index);//0
alert(matchs[0]);//cat
alert(pattern.lastIndex);//0

function htmlEscape(text) {
    return text.replace(/[<>\"&]/g, function(match, pos, originanText) {
        switch(match) {
            case "<" : return "&lt;";
            case ">" : return "&gt;";
            case "&" : return "&amp;";
            case "\"" : return "&quto;";
        }
    });
}

var txt =  "<p class=\"greeting\">Hello World!</p>";
alert(htmlEscape(txt));

var text = "red, blue, green, yellpw";
alert(text.split(/[^\,]+/));

var url = 'http://ce.sysu.edu.cn/hope/#-&424 2';
alert(encodeURI(url));
alert(decodeURI(encodeURI(url)));
alert(encodeURIComponent(url));
alert(decodeURIComponent(encodeURIComponent(url)));

function selectFrom(lowerValue, upperValue) {
    var dis = upperValue - lowerValue;
    return Math.floor(Math.random() * dis + lowerValue);
}

var colors = ["red", 'blue', 'yellow', 'brown', 'black', 'green'];
alert(colors[selectFrom(0, colors.length - 1)]);