Uncaught TypeError: undefined is not a function ---Substring="ABC"

1. I am learning js programming.
   
   
   
   2. I wrote a small code for the task...
   
   
   3. can you guys tell whether its correct..
   
   
   
   

Given a string Sting="ABCSC" Check whether it contains a Substring="ABC"?

1)If no , return "-1". 2)If yes , remove the substring from string and return "SC". use very simple code and concept(ALGORITHM)..

http://ift.tt/1BB7YEv

var string="ABCSC";
var n = string.indexof("ABC");

if (n != -1)
{
    var removedString = string.substring(1, 3);
    console.log(removedString);
}
else{
    console.log("-1");
}