การทำ checkbox ให้เป็นฟังก์ชั่น ใน dynamic elements ต้องทำยังไงคะ

<script language="javascript">

function CreateNewRow()
	{
		var intLine = parseInt(document.frmMain.hdnMaxLine.value);
		intLine++;
			
		var theTable = document.getElementById("tbExp");
		var newRow = theTable.insertRow(theTable.rows.length)
		newRow.id = newRow.uniqueID

		var newCell
		
		//*** Column 1 ***//
		newCell = newRow.insertCell(0);
		newCell.id = newCell.uniqueID;
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<center><SELECT NAME=\"txtLevel_"+intLine+"\" ID=\"txtLevel_"+intLine+"\"></SELECT></center>";

		//*** Column 2 ***//
		newCell = newRow.insertCell(1);
		newCell.id = newCell.uniqueID;
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<center><INPUT TYPE=\"TEXT\" SIZE=\"15\" NAME=\"txtItemRef_"+intLine+"\" ID=\"txtItemRef_"+intLine+"\"  VALUE=\"\"></center>";
		
		//*** Column 3 ***//
		newCell = newRow.insertCell(2);
		newCell.id = newCell.uniqueID;
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<center><SELECT style=\"width:300px;\" NAME=\"txtRelevantKey_"+intLine+"\" ID=\"txtRelevantKey_"+intLine+"\" ></SELECT></center>";

		//*** Column 4 ***//
		newCell = newRow.insertCell(3);
		newCell.id = newCell.uniqueID;
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<center>  <textarea rows =\"2\" cols =\"80\" NAME=\"txtDescription_"+intLine+"\" ID=\"txtDescription_"+intLine+"\"  VALUE=\"\">  </textarea>    </center>";
		
	
//*** Create Option ***//
	  
		CreateSelectOptionRelevantKey("txtRelevantKey_"+intLine)
		fncCreateSelectOptionLevel("txtLevel_"+intLine)
	
		
		document.frmMain.hdnMaxLine.value = intLine;
	}
	
          function fncCreateSelectOptionLevel(ele)
	{
			var objSelect = document.getElementById(ele);
			
			var Item = new Option("+"); 
			objSelect.options[objSelect.length] = Item;

			var Item = new Option("++"); 
			objSelect.options[objSelect.length] = Item;
}


		function CreateSelectOptionRelevantKey(ele)
	{
		var objSelect = document.getElementById(ele);
		var Item = new Option("", ""); 
		objSelect.options[objSelect.length] = Item;
		
		<?php
		 
		$objQuery = mysql_query($strSQL);
		while($objResult = mysql_fetch_array($objQuery))
		{  ?>
		
		var Item = new Option("<?php echo $objResult["keyName"];?>", 
		"<?php echo $objResult["keyID"];?>"); 
		
		objSelect.options[objSelect.length] = Item;
		<?php
		} ?>
	}

</script>