Sample js instance properties and prototype properties
- 2020-03-30 04:20:09
- OfStack
Please read the comments carefully for more details, so I'll cut the crap here and go straight to the code.
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//Properties are essentially the same as methods, which are functions whose properties are referential. < br / >
//An object has four properties:
// 1, the constructor
by the property defined by this keyword
// 2, the constructor defined by the var keyword property
// 3, the properties added by the constructor's prototype object
// 4, object dynamically added properties
//Public property of the instance: 1& NBSP; Property & PI defined by this keyword; To access 1,2,3,4
//Private property of the instance: 2& PI; Properties defined by the var keyword. To access 2 < br / >
//The Shared property of the instance: 3& NBSP; Properties added by the stereotype pointed to by the instance. To access 1 and 4 < br / >
//Static property of the instance: 4& NBSP; Object dynamically adds properties. To access 1 and 4
//Conclusion:
// Instance property: 1, public
// 2, private
// 4, static
// Stereotype attributes: 3, Shared
//This is defined as a privileged property. All accessible
//Var defines a private property. < br / >
//Dynamically added properties are public properties. Private properties cannot be accessed
//The stereotype properties that the instance object points to are the stereotype properties. Private properties are not accessible and have a lower priority than public properties
//Instance attribute mainly consists of public attribute and privilege attribute. Both are accessible by external and stereotype properties. The main difference is whether the private property
is accessible
//Stereotype properties have a lower priority than instance properties. Can be accessed externally and by instance properties (except private properties)
//-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- here for line -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- < br / >
//Public attributes: attributes of an object exposed to the external environment. It's also a property of an object. < br / >
//Private properties: properties inside an object that are often inaccessible. It makes sense to consider them at the constructor level. < br / >
//Static properties: properties that are added dynamically. It's also a property of an object. < br / >
//Common properties: properties Shared by all construction-generated instances.
function User(){
// Public property: every new User instance object has an attribute. < br / >
// Is an instance property, all instance properties do not share memory. < br / >
// Externally accessible. < br / >
this.name='byronvis';
// Privileged methods: for each new User instance object, there are methods. < br / >
// For instance methods, all instance methods do not share memory. < br / >
// Externally accessible. < br / >
// Public properties are accessible. < br / >
// Private properties are accessible. < br / >
this.sayName=function(){
alert(this.name);
alert(this.school);
alert(age);//The variable declaration is automatically advanced. < br / >
alert(this.sex);
};
// Private property: not externally accessible. < br / >
// Only makes sense for the constructor, not for the User instance object of new. < br / >
var age=22;
// Private method: not externally accessible. < br / >
// Only makes sense for the constructor, not for the User instance object of new. < br / >
function sayAge(){
alert(age);
}
sayAge();
}
// Shared property: Shared memory. < br / >
User.prototype.school='zky';
// Common methods: public properties can be accessed. < br / >
// Shared memory. < br / >
User.prototype.saySchool=function(){
alert(this.school);
alert(this.name);
alert(this.sex);
alert(age);
};
var obj=new User();
// Static properties: are instance properties that are added dynamically. < br / >
obj.sex='man';
// Static methods: are dynamically added instance methods. < br / >
obj.saySex=function(){
alert(this.sex);
alert(this.name);
alert(this.school);
alert(age);
};
//-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- here for line -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- < br / >
//// Proving that the properties defined by this keyword are essentially the same as the dynamically added properties can be considered public properties of an instance object. < br / >
// Verify: the properties defined by this keyword access dynamically added properties
// obj.sayName();//true
// Validation: dynamically added properties access the properties defined by this keyword
// obj.saySex();//true
// Validation: the public property accesses the private property
// obj.sayName();//true
obj.saySex();//false
// Verify: the Shared property accesses the private property
// obj.saySchool();//false
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Test documentation
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