Highlight Every Other Row

I've done this before but I can't quite remember how.  Below is an actual query from the site.  I need to highlight every other row that comes from the query with style="background-color: #fafafa;"

////// THE QUERY PART

      $m = $_POST['m'];
      $w = $_POST['w'];
      $mc = $_POST['mc'];
      $pr = $_POST['pr'];
      $pi = $_POST['pi'];
      $ma = $_POST['ma'];
      $u = $_POST['u'];
                        
      
                        $query_mem_1 = "SELECT `name`, `id`, `noreq`, `desc`, `partnum`, ";
                        if ($m == 1){ $query_mem_1 .= "`mfc`, `mfcdesc`, `mfcprtnum`, "; }
                        if ($w == 1){ $query_mem_1 .= "`lbs`, "; }
                        if ($mc == 1){ $query_mem_1 .= "`mchtime`, "; }
                        if ($pr == 1){ $query_mem_1 .= "`lstprc`, "; }
                        if ($pi == 1){ $query_mem_1 .= "`prcinc`, "; }
                        if ($ma == 1){ $query_mem_1 .= "`matcst`, "; }
                        if ($u == 1){ $query_mem_1 .= "`usdin`, "; }
                        $query_mem_1 .= "CAST(SUBSTRING(`partnum`, LOCATE('-', `partnum`) + 1) AS SIGNED) AS `sort_part` FROM `$parts_database_table` WHERE `name`=\"$n\" ORDER BY `sort_part` ASC";
                        mysql_select_db($database_name, $connection);
                        $mem_1 = mysql_query($query_mem_1, $connection) or die(mysql_error());
                        $row_mem_1 = mysql_fetch_assoc($mem_1);
                        $totalRows_mem_1 = mysql_num_rows($mem_1);

////////THE LOOP PART

if ($mem_1){
                      $numOfRows = mysql_num_rows ($mem_1);
                      for ($i = 0; $i < $numOfRows; $i++){
                      $name = mysql_result ($mem_1, $i, "name");
                        $noreq = mysql_result ($mem_1, $i, "noreq");
                        $partnum = mysql_result ($mem_1, $i, "partnum");
                      $desc = mysql_result ($mem_1, $i, "desc");
                        if ($w == 1){$lbs = mysql_result ($mem_1, $i, "lbs");}
                      if ($m == 1){$mfc = mysql_result ($mem_1, $i, "mfc");}
                        if ($m == 1){$mfcprtnum = mysql_result ($mem_1, $i, "mfcprtnum");}
                      if ($m == 1){$mfcdesc = mysql_result ($mem_1, $i, "mfcdesc");}
                        if ($u == 1){$usdin = mysql_result ($mem_1, $i, "usdin");}
                      $id = mysql_result ($mem_1, $i, "id");
                        if ($mc == 1){$mchtime = mysql_result ($mem_1, $i, "mchtime");}
                      if ($ma == 1){$matcst = mysql_result ($mem_1, $i, "matcst");}
                        if ($pi == 1){$prcinc = mysql_result ($mem_1, $i, "prcinc");}
                      if ($pr == 1){$lstprc = mysql_result ($mem_1, $i, "lstprc");}
                        $desc = htmlentities($desc);
                        $mfcdesc = stripslashes($mfcdesc);

////// THE COMES THE ACTUAL DISPLAY OF EACH ROW AND ENDING OF THE SECTION