function compare(value1, value2){
  if (value1<value2){
    return -1;
  }
  if (value1>value2){
    return 1;
  } else{
    return 0;
  }
}
var values = [0,1,5,10,15];
values.sort(compare);
console.log(values); // [0,1,5,10,15]

function compare(value1, value2){
  if (value1<value2){
    return 1;
  }
  if (value1>value2){
    return -1;
  } else{
    return 0;
  }
}

var colors = ["red", "green", "blue", "yellow", "purple"];
var colors2 = colors.slice(1);
var colors3 = colors.slice(1,4);

console.log(colors2); // green, blue, yellow, purple
console.log(colors3); // green, blue, yellow

var colors = ["red", "green", "blue"];
var removed = colors.splice(0,1);
console.log(colors); // greeen, blue
console.log(removed); // red

var colors = ["red", "green", "blue"];
var removed = colors.splice(1,0,"yellow", "orange");
console.log(colors); // ["red", "yellow", "orange", "green", "blue"]
console.log(removed); // 返回空

var colors = ["red", "green", "blue"];
var removed = colors.splice(1,1,"yellow", "orange");
console.log(colors); // ["red", "yellow", "orange", "blue"]
console.log(removed); // ["green"]

var pattern1 = /[bc]/i;
var pattern2 = new RegExp("[bc]at", "i");

var pattern1 = /[bc]/i;
var pattern2 = new RegExp("\\[bc\\]at", "i");

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

var matches = pattern1.exec(text);
console.log(matches); // ["cat"]

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

var matches2 = text.match(pattern1);
console.log(matches2); // ["cat"]

var text = "000-00-0000";
var pattern = /\d{3}-\d{2}-\d{4}/;

if (pattern.test(text)){
  console.log("The pattern was matched"); // The pattern was matched
}

(function() {
  var slice = Array.prototype.slice,
    aArguments = slice.apply(arguments);

    console.log(aArguments);
})(10, 20, 30);
arguments.callee

function sayName(name){
  alert(name);
}

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

function sayHi(){
  alert("hi");
}

console.log(sayName.length); //1
console.log(sum.length); //2
console.log(sayHi.length); //0

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]); 
}

console.log(callSum1(10,10)); // 20
console.log(callSum2(10,10)); //20
window.color = "red";
var o = {color:"blue"};

function sayColor(){
  console.log(this.color);
}

sayColor(); // red

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

var value = "25";
var number = Number(value);
console.log(typeof number);
console.log(number instanceof Number);// false

var obj = new Number(value);
console.log(typeof obj);
console.log(obj instanceof Number);// true

var falseObject = new Boolean(false);
var result = falseObject && true; // true 

//布尔表达式中的所有对象都会被转换为true, 因此falseObject对象在布尔表达式中代表的是true

console.log(result); // true

var falseValue = false;
result = falseValue && true;
console.log(result); //false

console.log(typeof falseObject); //object
console.log(typeof falseValue); // Boolean
console.log(falseObject instanceof Boolean); //true
console.log(falseValue instanceof Boolean); // false

var numberObject = new Number(10);
var numberValue = 10;
console.log(typeof numberObject); // Object
console.log(typoef numberValue); // number
console.log(numberObject instanceof Number); // true
console.log(numberValue instanceof Number); // false

var stringValue = "hello world";
console.log(stringValue.charAt(1)); // e
console.log(stringValue.charCodeAt(1)); // 101

var stringValue = "hello ";
var result = stringValue.concat("world");
console.log(result); // hello world
console.log(stringValue); // hello

var str="Hello happy world!";
console.log(str.slice(6)); // happy world!
console.log(str.slice(6,11));// happy
console.log(str.slice(-3)); // ld!
console.log(str.slice(3, -4)); //lo happy wo 

var str="Hello happy world!";
console.log(str.substring(6)); // happy world!
console.log(str.substring(6,11));// happy
console.log(str.substring(-3)); // Hello happy world!
console.log(str.substring(3, -4)); //Hel

var str="Hello world!";
console.log(str.substr(3)); //lo world!
console.log(str.substr(3, 7)); //lo worl
console.log(str.substr(-3)); // ld!
console.log(str.substr(3, -3)); // 空字符串

indexOf() lastIndexOf()

var stringValue = "hello world";
console.log(stringValue.indexOf("o")); // 4
console.log(stringValue.lastIndexOf("o")); //7

var stringValue = "hello world";
console.log(stringValue.indexOf("o", 6)); // 7
console.log(stringValue.lastIndexOf("o", 6)); //4

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

var matches = text.match(pattern);
console.log(matches.index); //0
console.log(matches[0]); // cat
console.log(pattern.lastIndex); //0

var text = "cat, bat, sat, fat";
var pos = text.search(/at/);
console.log(pos); // 1

var text = "cat, bat, sat, fat";
var result = text.replace("at", "ond");
console.log(result); // cond, bat, sat, fat

var result = text.replace(/at/g, "ond");
console.log(result); // cond, bond, sond, fond

var url = "http://www.baidu.com/";
console.log(encodeURI(url));
console.log(encodeURIComponent(url));
encodeURI()和encodeURIComponent()方法对象的两个方法分别是decodeURI()和decodeURIComponent()

值=Math.floor(Math.random()*可能值的总数+第一个可能的值)

var num = Math.floor(Math.random()*10+1);
function selectFrom(lowerValue,upperValue){
  var choice = upperValue - lowerValue + 1;
  return Math.floor(Math.random()*choice+lowerValue);
}
var num = selectFrom(2,10);
console.log(num);
var colors = ["red", "green", "blue", "yellow", "black", "purple", "brown"];
var color = colors[selectFrom(0, colors.length-1)];
console.log(color);