Multiple instances of a character?

JavaScript
1

Trying to get all instances of a blank space using indexOf and a for loop and add it to arrofSpacIndex array

function allInstancesOfBlankSpace (words) 
{
  var j=0;
 
  var arrOfSpaceIndex = [];
  //creating an array to store all instances of blank spaces
  for(i=0;  j = -1; i = pos)
 
  {
    var pos = words.indexOf('', i )
   //gets integer of next instance of character want it to be separate from j so position of i doesnt get set to -1
  
   var j= words.indexOf('', i )
   //checks if there is another instance of the blank space if none then -1 which should stop loop from iterating
   
   
    arrOfSpaceIndex.push(pos)
    //adds position of blank space to array
  }

 return arrOfSpaceIndex
}



allInstancesOfBlankSpace("HELLO MY FRIEND")