Question about str[] in a loop.

gistfile1.txt

function findLongestWord(str) {
  var length = 10;
  var biggest = 0;
  var j = 0;
  if (str[j] != " ") {   // THIS WORKS AS EXPECTED
        biggest += 1;
  }
  
  for (var i = 0; i > str.length; i++) {  // THIS DOESN't WORK. 
      if (str[i] != " ") {             // IF I REMOVE THE ABOVE IF STATEMENT
        biggest += 1;  //  BIGGEST = 0
  }
    
  }
  return biggest;
}

findLongestWord("The quick brown fox jumped over the lazy dog");