Find if an item is in an array and return it's index or -1 if not found

inArray.js

/* Returns either the index of the location in the array,
  or -1 if the array did not contain the targetValue,
  using a binary seach algorithm */
var inArray = function(array, targetValue) {
	var min = 0;
	var max = array.length - 1;
    var guess;
    
    while(max >= min) {
        
        guess = min + Math.floor((max - min) / 2);
        
        if (array[guess] === targetValue) {
            console.log('It took ' + counter + ' guesse(s)');
            return guess;   
        } else if (array[guess] < targetValue) {
            min = guess + 1;
        } else {
           max = guess - 1;
        }   
    }
    
	return -1;
};

var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
		41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97];

var result = inArray(primes, 73);
console.log("Found prime at index " + result);