详解js访问对象的属性和方法

var object = {name:'xiaoming',age:29};
var name1 = object.name;var name2 = object['name'];

function Person(){
  this.name = 'xiaoming';
  this.age = 29;
  this.say = function(){
    alert('This is person');
  }     
}
var student = new Person();
alert(student.name);
alert(student['age']);
student.say(); //使用" . "访问对象方法

var str = 'Thisthebesttimesewerty';
var obj = {};
for(var i=0; i<str.length;i++){
  var char = str[i];
 // var char = str.charAt(i); //charAt()可返回指定位置的字符，i为字符的下标，从0开始
  if(obj[char]){
    obj[char]++; //char是obj对象的一个属性，如果存在次数加1
  }else{
    obj[char] = 1; //如果不存在，保存在obj中并计数为1
  }
}
 
var max = 0;
var maxChar = null;
for(var key in obj){
  if(max < obj[key]){
    max = obj[key]; //出现最多次数max
    maxChar = key; //出现次数最多的字符maxChar
  }
}

function arraysSimilar(arr1,arr2){
  if(!(arr1 instanceof Array) || !(arr2 instanceof Array)){
     return false;
  }  
  if(arr1.length !== arr2.length){
     return false;
  }
 
  var i=0, n=arr1.length, countMap1={}, countMap2 = {}, t1, t2,
  TYPES = ['string','boolean','number','undefined','null','function','date','window'];
 
  for(i; i<n; i++){
     t1 = typeOf(arr1[i]);
     t2 = typeOf(arr2[i]);
     if(countMap1[t1]){
       countMap1[t1]++;
     } else{
       countMap1[t1] = 1;
     }
 
    if(countMap2[t2]){
       countMap2[t2]++;
     } else{
       countMap2[t2] = 1;
     }
  }
 
  for(i=0; i<TYPES.length; i++){
    if(countMap1[TYPES[i]] != countMap2[TYPES[i]]){
      return false;
    }
  }
  return true;
}
 
function typeOf(ele){
  var r;
  if(ele === null){
    r = 'null';
  }
  else if(ele === 'window'){
    r = 'window';
  }
  else if(ele instanceof Array){
    r = 'array';
  }
  else if(ele instanceof Date){
    r = 'date';
  }
  else{
    r = typeof(ele);
  }
  return r;
}