Usage of arguments keywords in javascript

since the JS call function can not be in accordance with the function of the definition format to pass parameters, for example:

function Test (A, b) {do   something}

Test (1);

Test (from);

Test ();

The above three call methods are correct, but if the test function uses a A, b parameter, the test () Call function may return a undefined error . So JS provides a keyword arguments to get the parameters passed in. Arguments is an array with the Length property, which can be obtained by arguments[index] to get the parameter values passed in by the function.

For example:

function addition (A, b) {   return a+b;//if a, B is not passed in will be an error! }//Improved Method Funciton Additionbetter (A, b) {   if (arguments.length==0)     return 0;   else if (arguments.length==1) {     return arguments[0];   } else{     return arguments[0]+arguments[1];}   }

Usage of arguments keywords in javascript