ช่วยอธิบาย java script ของ code นี้หน่อยค่ะ ว่ามีการทำงานอย่างไร

<script language = "JavaScript">
		function List(SelectValue)
		{
			form1.gen.length = 0
			
			
			//*** Insert null Default Value ***//
			var myOption = new Option('','')  
			form1.gen.options[form1.gen.length]= myOption
			
			<?
			$intRows = 0;
			$strSQL = "SELECT * FROM generation ORDER BY gen_id ASC ";
			$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
			$intRows = 0;
			while($objResult = mysql_fetch_array($objQuery))
			{
			$intRows++;
			?>			
				x = <?=$intRows;?>;
				mySubList = new Array();
				
				strGroup = <?=$objResult["c_id"];?>;
				strValue = "<?=$objResult["gen_id"];?>";
				strItem = "<?=$objResult["gen"];?>";
				mySubList[x,0] = strItem;
				mySubList[x,1] = strGroup;
				mySubList[x,2] = strValue;
				if (mySubList[x,1] == SelectValue){
					var myOption = new Option(mySubList[x,0], mySubList[x,2])  
					form1.gen.options[form1.gen.length]= myOption					
				}
			<?
			}
			?>																	
		}
		</script>