JavaScript--appyの使用

Js apply      

             :  

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  :  

<script type="text/javascript">   
/*      */   
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     .   
</script>   

  : 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      ,       ,         ,         ,  ,       ,        ,      ,          …     

           ,               ,                   (          ),                  ,     ,   ,   ,                       !