Super fast, iterative binary search. For those of you who are fed up with indexOf!

gistfile1.js

/**
 * Searches the specified range of a sorted array for a given value; if the
 * wanted value is found, its index is returned. -1 is returned if the item 
 * is not found. If no range is specified, the entire array will be searched.
 * Please note: the array that this method is invoked on must be sorted in 
 * ascending order!
 * @param {int|float|string} wanted The value to be searched for.
 * @param {int} [first] The start of the search range.
 * @param {int} [last] The end of the search range.
 * @return {int} The index of the element if found, otherwise -1.
 */
Array.prototype.binarySearch = function(wanted, first, last)
{   
    //if(typeof wanted !== typeof this[0])
    if(wanted == null)
       return -1 // Searching for nothing may introduce an infinite loop.
    if(first == null) 
       var first = 0;
    if(last == null) 
       var last = this.length - 1;
    else if(last < 0) 
       last += this.length;
	
	while(first <= last)
	{
                var middle = Math.floor((first + last) / 2);
        
		if(wanted < this[middle])
			last = middle - 1;
		else if(wanted > this[middle])
			first = middle + 1;
		else  // We've found her!
			return middle;
	}
	
	return -1;
}