基本类型及方法--《js高级程序设计》

Boolean

var falseObject = new Boolean(false);

var falseValue = false;

alert(typeof falseObject);   //object
alert(typeof falseValue);    //boolean
alert(falseObject instanceof Boolean);  //true
alert(falseValue instanceof Boolean);   //false

Date

//Date.now() is in ECMAScript 5
//Prior to that, use +new Date()

var now = (typeof Date.now == "function" ? Date.now() : +new Date());
alert("Right now: " + now);

apply call

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

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

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

alert(callSum1(10,10));   //20
alert(callSum2(10,10));   //20


function outer(){
    inner();
}

function inner(){
    alert(inner.caller);  //返回outer代码
}

outer();

function outer(){
    inner();
}

function inner(){
    alert(arguments.callee.caller); //返回outer代码
}

outer();

call

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

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

sayColor();            //red

sayColor.call(this);   //red
sayColor.call(window); //red
sayColor.call(o);      //blue

Number

var numberObject = new Number(10);
var numberValue = 99;

//toString() using a radix
alert(numberObject.toString());       //"10"
alert(numberObject.toString(2));      //"1010"
alert(numberObject.toString(8));      //"12"
alert(numberObject.toString(10));     //"10"
alert(numberObject.toString(16));     //"a"

//toFixed() 把数字转换为字符串，结果的小数点后有指定位数的数字
alert(numberObject.toFixed(2));    //outputs "10.00"

//toPrecision() 把数字格式化为指定的长度
numberObject = new Number(99);
alert(numberObject.toPrecision(1));    //"1e+2"
alert(numberObject.toPrecision(2));    //"99"
alert(numberObject.toPrecision(3));    //"99.0"

//toExponential() 	把对象的值转换为指数计数法
var num = new Number(10000);
console.log(num.toExponential(1))  //1.0e+4

alert(typeof numberObject);   //object
alert(typeof numberValue);    //number
alert(numberObject instanceof Number);  //true
alert(numberValue instanceof Number);   //false

RegExp

var text = "this has been a short summer";
var pattern = /(.)hort/g;

/*
 * Note: Opera doesn't support input, lastMatch, lastParen, or multiline.
 * Internet Explorer doesn't support multiline.
 */        
if (pattern.test(text)){
    alert(RegExp.input);               //this has been a short summer
    alert(RegExp.leftContext);         //this has been a            
    alert(RegExp.rightContext);        // summer
    alert(RegExp.lastMatch);           //short
    alert(RegExp.lastParen);           //s
    alert(RegExp.multiline);           //false
}


var text = "this has been a short summer";
var pattern = /(.)hort/g;

/*
 * Note: Opera doesn't support short property names.
 * Internet Explorer doesn't support multiline.
 */        
if (pattern.test(text)){
    alert(RegExp.$_);               //this has been a short summer
    alert(RegExp["$`"]);            //this has been a            
    alert(RegExp["$'"]);            // summer
    alert(RegExp["$&"]);            //short
    alert(RegExp["$+"]);            //s
    alert(RegExp["$*"]);            //false
}


var text = "this has been a short summer";
var pattern = /(..)or(.)/g;
      
if (pattern.test(text)){
    alert(RegExp.$1);       //sh
    alert(RegExp.$2);       //t
}


var text = "mom and dad and baby";

var pattern = /mom( and dad( and baby)?)?/gi;
var matches = pattern.exec(text);

alert(matches.index);    //0
alert(matches.input);    //"mom and dad and baby"
alert(matches[0]);       //"mom and dad and baby"
alert(matches[1]);       //" and dad and baby"
alert(matches[2]);       //" and baby"

var text = "cat, bat, sat, fat";        
var pattern1 = /.at/;

var matches = pattern1.exec(text);        
alert(matches.index);    //0
alert(matches[0]);       //"cat"
alert(pattern1.lastIndex);//0

matches = pattern1.exec(text);        
alert(matches.index);    //0
alert(matches[0]);       //"cat"
alert(pattern1.lastIndex);//0

var pattern2 = /.at/g;

var matches = pattern2.exec(text);        
alert(matches.index);    //0
alert(matches[0]);       //"cat"
alert(pattern2.lastIndex);//3

matches = pattern2.exec(text);        
alert(matches.index);    //5
alert(matches[0]);       //"bat"
alert(pattern2.lastIndex);  //8

var pattern1 = /\[bc\]at/i;

alert(pattern1.global);     //false
alert(pattern1.ignoreCase); //true
alert(pattern1.multiline);  //false
alert(pattern1.lastIndex);  //0
alert(pattern1.source);     //"\[bc\]at"

var pattern2 = new RegExp("\\[bc\\]at", "i");

alert(pattern2.global);     //false
alert(pattern2.ignoreCase); //true
alert(pattern2.multiline);  //false
alert(pattern2.lastIndex);  //0
alert(pattern2.source);     //"\[bc\]at"