Get boxes in the last column and row of a table of 3 columns

gistfile1.js

// Making fancy borders on the product listing page.
  var total = $(".ProductList li").length;
  var last_row = Math.ceil(total/3);
  var n;
  var current_row;
  
  $(".ProductList li").each(function(i){
    
    n = i+1;
    current_row = Math.ceil(n/3);
    
    // Get boxes in the last column.
    if( n%3 == 0 ){ 
      $(this).css("border-right","0 none"); 
    }
    
    // Get boxes in the last row
    if( current_row == last_row ){
      $(this).css("border-bottom","0 none"); 
    }
    
  });