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Why are these three concepts put together. The reason is that these will be used to implement JS inheritance.
2. Call and applyfunction fn( arg1, arg2,... ){ // do something}fn( arg1, arg2,... );fn.call( context, arg1, arg2,... );fn.apply( context, [ arg1, arg2,... ]);
Manual explanation:
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Call Method
Call a method of one object to replace the current object with another object.
Call ([thisobj [, arg1 [, arg2 [, [,. argn])
Parameters
Thisobj
Optional. Will be used as the object of the current object.
Arg1, arg2, and argn
Optional. The method parameter sequence will be passed.
Description
The call method can be used to call a method instead of another object. The call method can change the object context of a function from the initial context to the new object specified by thisobj.
If the thisobj parameter is not provided, the global object is used as thisobj.
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<!--by oscar999 2013-1-17--> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">From the above example, we can see that alert (this. A) does not return the value in the current function.
The call execution speed is slightly faster, but the difference is not big.
3. PrototypeJavaScript does not have the concepts of "subclass" and "parent class", nor does it distinguish between "class" and "instance, inheritance is implemented by a prototype chain mode.
Prototype is actually an attribute of the constructor.
All attributes and methods that need to be shared by instance objects are placed in this object; those attributes and methods that do not need to be shared are placed in the constructor.
Once an instance object is created, the attributes and methods of the prototype object are automatically referenced. That is to say, the attributes and methods of the Instance Object are divided into two types: local and referenced.function Person(name){this.name = name;this.gender = "male";}var person1 = new Person("MM");var person2 = new Person("YY");person1.gender = "female";alert(person2.gender);// male</script><script>function Person(name){this.name = name;}Person.prototype.gender = "female";var person1 = new Person("MM");var person2 = new Person("YY");alert(person2.gender);// male</script>Compare the above two examples.
4. Reference
Http://www.ruanyifeng.com/blog/2011/06/designing_ideas_of_inheritance_mechanism_in_javascript.html
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