CI框架中使用ajax操作数据库有关问题

<script><br />//调用方法用ajax操作add_dbdata.php<br />var xmlHttp<br />function add_dbdata(str,str1){<br />		<br />	//alert(str);<br />	if (str=="")<br />	{<br />	document.getElementById("txtHint").innerHTML="";<br />	return;<br />	}<br />	if (window.XMLHttpRequest)<br />	{// code for IE7+, Firefox, Chrome, Opera, Safari<br />	xmlhttp=new XMLHttpRequest();<br />	}<br />	else<br />	{// code for IE6, IE5<br />	xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");<br />	}<br />	xmlhttp.onreadystatechange=function()<br />	{<br />	if (xmlhttp.readyState==4 && xmlhttp.status==200)<br />	{<br />	document.getElementById("txtHint").innerHTML=xmlhttp.responseText;<br />	}<br />	}<br />	//xmlhttp.open("GET","add_dbdata.php?q="+str,true);<br />	//alert(str1);<br />	//alert(str);<br />	<br />	xmlhttp.open("GET","add_dbdata.php?q="+str,true);	   //xmlhttp.open("GET","<?=base_url()?>project_c/add_zijiedian/"+str1+str,true);  这样写，也不好使，不知道哪有问题 <br />	xmlhttp.send();<br />}

<br /><?php<br />header("Content-type:text/html;charset=utf8");<br />$q=$_GET["q"];<br />$q=(int)$q;<br />echo "<script>alter('kkkkkkk');</script> ";<br /><br /><br />$con = mysql_connect('localhost', 'root', '');<br />if (!$con)<br /> {<br /> die('Could not connect: ' . mysql_error());<br /> }<br /><br />mysql_select_db("test", $con);<br />mysql_query("set names utf8");<br /><br />//$sql = " SELECT * FROM ecm_acategory ";<br />$sql = " insert into data (name) values('999')";<br />echo $sql;<br />$result = mysql_query($sql);<br /><br /><br />mysql_close($con);<br />?><br /><br />