PersistentBugger.js

function persistence(num) {
    var mull=1;
    var count=0;
    num=num.toString();
    while(true){
    for (var i=0;i<num.length;i++){
        mull*=parseInt(num[i]);}
      if (mull<=9){
      count++;
      if (num.length==1){count--;};
      return count;}
      else{
      num=mull.toString();
      mull=1;
      count++;}}}

/*

Write a function, persistence, that takes in a positive parameter 
num and returns its multiplicative persistence, which is the number 
of times you must multiply the digits in num until you reach a single 
digit.

For example:

 persistence(39) === 3 // because 3*9 = 27, 2*7 = 14, 1*4=4
                       // and 4 has only one digit

 persistence(999) === 4 // because 9*9*9 = 729, 7*2*9 = 126,
                        // 1*2*6 = 12, and finally 1*2 = 2

 persistence(4) === 0 // because 4 is already a one-digit number

 */