Jsアプリ()使用詳細

Js apply    
       javascript   apply call ,     ,     ,            apply   call     ,          ,         ,       ..                              ,      ..

             :

1.apply call      

2.      apply,      call

3.apply       （            apply）

          apply call   ,                     .

         apply:              ，           .

 Function.apply(obj,args)         
obj：       Function  this  
args：     ，        Function（args-->arguments）

         call: apply     ,           .

 Function.call(obj,[param1[,param2[,…[,paramN]]]])
obj：       Function  this  
params：         

1.apply  :

 
/*      */ 
function Person(name,age) { 
    this.name=name; this.age=age; 
} 
 /*       */ 
functionStudent(name,age,grade) { 
    Person.apply(this,arguments); this.grade=grade; 
} 
//        
var student=new Student("qian",21,"   "); 
//   
alert("name:"+student.name+"
"+"age:"+student.age+"
"+"grade:"+student.grade); 
//          name:qian age:21 grade:    
//         name age     ,              ,    apply     . 
 

  : Person.apply(this,arguments);

this:              student

arguments:     ,   [“qian”,”21”,”   ”];

          : student   Person        , Person       this.name      ,          student    

 

2.call  

 Studen       apply      :

Person.call(this,name,age);

   ok 

3.      apply,      call

          ,             ,  apply         arguments,         ,     Person              (   Person Student            )       apply ,     Person         (age,name), Student      (name,age,grade),      call    ,                 (Person.call(this,age,name,grade));

4.apply         

           ,    apply     ,        (this),             , 

   Person   ,          ,                              ,

    apply        ,                   ([param1,param2,param3]     param1,param2,param3)                      ,         ,         ,  apply     ,             :

 

a)Math.max               

  Math.max        Math.max([param1,param2])      

     Math.max(param1,param2,param3…),        apply         var max=Math.max.apply(null,array),                   

(apply                        )

                          null,                ,             ,         ,.         null  

b)Math.min                

    max      var min=Math.min.apply(null,array);

c)Array.prototype.push           

  push      push    ,      push(param1,param,…paramN)          apply         , :

vararr1=new Array("1","2","3"); 
 vararr2=new Array("4","5","6"); 
Array.prototype.push.apply(arr1,arr2); 

       ,arr1   push  ,     apply             .

        ,    apply  Math.min        :

          n     ,           （[param1[,param2[,…[,paramN]]]]）,    apply            !


5.  :

     apply      ,       ,         ,         ,  ,       ,        ,      ,          …   

           ,               ,                   (          ),                  ,     ,   ,   ,                       !