/*
 * Reference from http://iamseanmurphy.com/2009/04/29/binary-search-for-javascript-arrays/
 */

Array.prototype.binarySearch = function(needle, case_insensitive) {  
    if (!this.length) return -1;  
  
    var high = this.length - 1;  
    var low = 0;  
    case_insensitive = (typeof(case_insensitive) !== 'undefined' && case_insensitive) ? true:false;  
    needle = (case_insensitive) ? needle.toLowerCase():needle;  
  
    while (low <= high) {  
        mid = parseInt((low + high) / 2);
        element = (case_insensitive) ? this[mid].toLowerCase():this[mid];  
        if (element > needle) {  
            high = mid - 1;  
        } else if (element < needle) {  
            low = mid + 1;  
        } else {  
            return mid;  
        }  
    }  
  
    return -1;  
};