Largest number

var arrayInput = [3,30,34,5,9];
var largestNumberString = "";

for (var i=0; i<arrayInput.length;i++) {
    largestNumberString += getMaxFirstNumber(arrayInput);
}

function getMaxFirstNumber(array) {
  var index = 0;
  var maxNumber=array[0];
  for (var i=0; i<array.length;i++) {
     for (var j=i; j<array.length;j++) {
       if (getFirstNumber(array[i]) < getFirstNumber(array[j]) && getFirstNumber(maxNumber) < getFirstNumber(array[j])) {
           maxNumber=array[j];
           index = j;
        } else if (getFirstNumber(array[i]) === getFirstNumber(array[j])) {
           if (array[i] % 10 < array[j] % 10 && maxNumber < array[j]) {
		maxNumber=array[j];
                index = j;
           }
        }
     }
  }
  array[index] = -1;
  return maxNumber;
}

function getFirstNumber(number) {
    if ((number - number % 10) / 10 === 0) {
    	return number;
    } else {
       return (number - number % 10) / 10;
    }
}