Find Issue in FF

arrErr.js

var fg = function(s){
  var d = s+1; 
  return d;
};
 
var callFunc = function (f) {
   var i,arr; 
   arr = [];
    for(i=0;i<1;i+1){
      arr.push(f(i));
      arr.push(f(i));
    } 
    console.log(arr);
   return arr;	    
};
 
var z = callFunc(fg);