How objects in js are declared and some usage examples for arrays

  • 2020-03-30 00:49:06
  • OfStack

 
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<script> 
//Define a print function
var $=function(str){ 
document.write(str); 
document.write("<br/>"); 
} 
//Defines the print array function
var _=function(arr){ 
for(var tmp in arr) 
{ 
$(arr[tmp]); 
} 
} 
//Define a student object
var stu=new Object(); 

//Declare properties and behaviors
stu.id=16; 
stu.name=' Light currency '; 
stu.age=function(){ 
return this.id; 
} 

//Print student information
$(stu.id); 
$(stu.name); 
$(stu.age());//Call with parentheses

stu.sex=' female '; //Add a new property
$(stu.sex); //Print the newly added properties

//Scheme 2:
function Student(id,name) 
{ 
this.id=id; 
this.name=name; 
this.getAge=function(){ 
return this.id; 
} 

} 

// use  
var stu2=new Student(1,' Yang, '); 
$(stu2.id); 
$(stu2.name); 
$(stu2.getAge()); 
//Define one more property
stu2.sex=' transsexuals '; 
$(stu2.sex); 
//How do dynamic languages cross domains?
Student.prototype.address=" Afghanistan "; 
$(stu2.address); 
$("stu2_1 begin..."); 
var stu2_1 =new Student(1,' Yang, '); 
$(stu2_1.id); 
$(stu2_1.name); 
$(stu2_1.getAge()); 
$(stu2_1.sex); 
$(stu2_1.address); //Cross-domain access, b objects access the properties of a objects
//In the definition
$("stu2_1 end..."); 

//Scenario 3: json
var stu3={id:1,name:' Mao Yanyan ',getName:function(){return this.name;}}; 
$(stu3.id); 
$(stu3.name); 
$(stu3.getName()); 

//var stu2 

//Many functions in js have the same name as functions in Java
var str1=new String("abcd") 
var str2="asdf"; 
$(str1.indexOf('c')); 
$(str1.charAt(3)); 
$ (str2.charAt(3)); 
$("absdf".substring(2,4)); 

var day=new Date(); 
$(day.getYear()); 
$(day.toLocaleString()); 


//Talk about an array
var arr1=new Array(3); 
arr1[0]=10; 
arr1[1]=20; 
arr1[2]=3; 
_(arr1); 
arr1[3]=4; 
// 
_(arr1); 

//An array of 2
var arr2=new Array(234,345,2354,2134,234); 
_(arr2); 

//An array of 3
var arr3=new Array(); 
arr3[0]=10; 
arr3[1]=20; 
arr3[2]=3; 
_(arr3); 

//Array 4. Recommended writing
var arr4=[]; 
arr4[0]=10; 
arr4[1]=20; 
arr4[2]=3; 
_(arr4); 

//Array 5. Recommended writing
var arr5=[3254,43,532,45,2345]; 
_(arr5); 

function add(i,j){ 
return i+j; 
} 

function add(i,j,k){ 
return i+j+k; 
} 

$(add(1,2));//Automatically identify the number of parameters

var Person=function(id,name) 
{ 
this.id=id;//public 
this.name=name;//public 
var i=1;//private 
function test(){//private 
alert('asdf'); 
} 
this.t=function()//public 
{ 
return 1; 
} 
} 
var p=new Person(1," Chen xin "); 
$(p.id); 
$(p.name); 
$(p.t());//Normal access
$(p.test()); //Can not access
</script> 
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