//**************************************
    //     
    // Name: Binary search
    // Description:Binary search algorithm f
    //     unction. Takes an array as an argument a
    //     nd the element 
    to be searched for in the array. Returns '1' if found, '0' if not. 
    The code can be modified slightly to return the array index of the found element.
    // By: Bhushan Paranjpe
    //
    //This code is copyrighted and has    // limited warranties.Please see http://
    //     www.Planet-Source-Code.com/xq/ASP/txtCod
    //     eId.755/lngWId.8/qx/vb/scripts/ShowCode.
    //     htm    //for details.    //**************************************
    //     
    
    <?php
    function BinarySearch($ArrayToSearch/*array to search through*/, $SearchFor/*element to search for*/)
    {
    sort($ArrayToSearch);//must sort the array
    //index	 
    $first=0;
    $last=count($ArrayToSearch)-1;
    $mid=($first+$last)/2;
    $SearchFor=strval(trim($SearchFor)); 
    while
    (
    ($first<=$last)&&
    	 (strval(trim($ArrayToSearch[$mid]))!=$SearchFor)
    )	 
    {
    if(strcmp(strtolower($SearchFor),strtolower($ArrayToSearch[$mid]))<0)
    	 {$last=$mid-1;}//search the upper half 
    	 else
    	 if(strcmp(strtolower($SearchFor),strtolower($ArrayToSearch[$mid]))>0)
    	{$first=$mid+1;}//search the lower half
    	 $mid=($first+$last)/2;//new mid point
    }	
    if(strval(trim($ArrayToSearch[$mid]))==$SearchFor) 	
    //{return $mid;} --> if your objectiv
    //     e is to return the index 
    	{return 1;}
    else
    {return 0;}
    //{return -1;} --> if your objective 
    //     is to return the index 
    }
    ?>