Remarkably wrong FizzBuzz

badfizzbuzz.js

function counter(){
  for (i=0; i<100; i++) { 
    var countThree=i/3; 
    var countSeven=i/7; 
    if (countThree.indexOf(“.”)==null){ 
      document.write(i + “fizz”);
     } else { 
       if (countSeven.indexOf(“.”)==null){ 
         document.write(i + “buzz”); 
       } else { 
         document.write(i); 
       } 
     } 
  }
}