[JavaScript] Some prototype descriptions

  VaR  Point  =     Function  (X, y ){
  This  . X  =  X;
  This  . Y  =  Y;
}
Point. Name  =    '  I am name  '  ;
Point. Prototype. Sum  =     Function  (){
  Return     This  . X  +     This  . Y;
}
Point. Prototype. Odd  =    Function  (){
Alert (  This  . Sum ());
}
  VaR  A  =     New  Point (  1  ,  2  );
A. Odd ();  VaR  B =     New  Point (  3  ,  4  );
B. Odd ();

Point. Prototype  =  {  //  This process will overwrite the previous method (sum, odd)  
  Plus:  Function  (){
  Return    This  . X  -     This  . Y;
},
Odd2:  Function  (){
Alert (  This  . Plus ());
}
}
B. Odd ();  //  There will be no exception here  
    VaR C  =     New  Point (  5  ,  3  );
C. odd2 ();  //  There will be no exception here  
  Alert (C. Name );  //  Exception undefined can draw a conclusion point. Name! = Point. Prototype. Name  
   //  Point. Prototype. Name is used after instantiation, and point. Name is equivalent to its own static variable.  
  C. Odd ();  //  An exception occurs here. 

1. prototype: the attributes added by prototype are the same as those of the instantiated functions (attributes). If it is point. Sum, sum cannot be called in new point.