JavaScript Learning Note--arguments

   //FN (+/-)//Argument   functionFN (a,b,c) {//Formal Parametersalert.log (arguments)//Popup [Object Arguments], is a collection of arguments arguments=>[1,2]Console.log (arguments)//[A]Alert (arguments.length)//arguments and LengthsAlert (Arguments[1])//in the actual parameter 2   }   //when the number of arguments to a function cannot be determined: arguments   functionsum () {varN=0;  for(vari=0;i<arguments.length;i++) {n+=Arguments[i]}returnN; } console.log (SUM (1,2,3,4,5)); //Scope    varA=1; functionFn2 (a) {arguments[0]=3; alert (a); //3        vara=2;//In Line code parsing, this changes only the FN2 function to pre-parse the value of a in a=2, and does not change the value of a in the global pre-parseAlert (arguments[0]);//2} fn2 (a); alert (a); //1

JavaScript Learning Note--arguments