Arguments. callee arguments. Caller call aply

Reposted from arguments, callee, caller, call, And appy in Javascript, a small programmer reads an article on the Internet <fully understand the concepts of JavaScript caller, callee, call, and apply>, write down the code.
<Script language = "JavaScript">
/*
* Demonstrate the usage of arguments and how to obtain real parameters and number of shapes
*/
Function argtest (A, B, C, D ){
VaR numargs = arguments. length; // obtain the value of the passed parameter.
VaR expargs = argtest. length; // obtain the value of the expected parameter.
Console. Log ("the number of real parameters is:" + numargs)
Console. Log ("Quantity:" + expargs)

Console. Log (arguments [0])
Console. Log (argtest [0]) // undefined does not have this usage
}
// Argtest (1, 2)
// Argtest (1, 2, 3, 4, 5)

/*
* Arguments is not an array (array class)
*/

Array. Prototype. selfvalue = 1;
Function testaguments (){
Console. Log ("arguments. selfvalue =" + arguments. selfvalue );
}
// Console. Log ("array. sefvalue =" + new array (). selfvalue );
// Testaguments ();





/*
* Demonstrate the caller attribute of the function.
* Description: (current function). Caller: returns a reference to the function, which calls the current function.
*/

Function callerdemo (){
If (callerdemo. Caller ){
VaR A = callerdemo. Caller. Arguments [0];
Console. Log ();
} Else {
Console. Log ("this is a top function ");
}
}
Function handlecaller (){
Callerdemo ();
}

// Callerdemo ();
// Handlecaller ("parameter 1", "parameter 2 ");


/*
* Shows the callee attribute of the function.
* Description: arguments. callee: the initial value is the function object being executed. It is used for anonymous functions.
*/
Function calleedemo (){
Console. Log (arguments. callee );
}
// Calleedemo ();
// (Function (arg0, arg1) {console. Log ("Quantity:" + arguments. callee. Length )})();


/*
* Demonstrate the usage of the apply and call Functions
* Note: The function is used to bind a function to another object for running. (calling a function within a specific scope is actually equivalent to setting the this value in the function body.) The two are different only when defining parameters:
* Apply (thisarg, argarray );
* Call (thisarg [, arg1, arg2…] ]);
* That is, the this pointer inside all functions will be assigned to thisarg.
*/

Function objecta (){
Console. Log ("execute objecta ()");
Alert (arguments [0]);
This. Hit = function (MSG) {alert (MSG )}
This.info = "I'm from objecta"
}
 
Function objectb (){
Alert ("execute objectb ()");
// Call the objecta () method, and all this in the objecta constructor will be replaced by this in objectb.
Objecta. Apply (this, arguments); // objecta. Call (this );
Alert (this.info );
}
// Objectb ('parameter 0 ');


VaR value = "global variable ";
Function OBJ (){
This. value = "object! ";
}
Function fun1 (){
Alert (this. value );
}
// Fun1 ();
// Fun1.apply (window );
// Fun1.apply (New OBJ ());
</SCRIPT>