Script does not refresh the page before and after the linkage code _javascript tips

Copy Code code as follows:

<asp:dropdownlist id= "type1" runat= "cssclass=" tfont "onchange=" link (this.id); "</asp:DropDownList>
<%--Size class--%>
<script>
function link (id)
{
var obj = document.getElementById (ID);
var obj1 = document.getElementById (' type2 ');
var name = "";
for (i = 0; i < obj.options.length; i++)
{
if (obj.options[i].selected)
{
name = Obj.options[i].value;
}
}
var names = Bargain_class.link (name). Value.split (', ');
var obj1_count = Obj1.options.length
for (i = 0; i < Obj1_count; i++)
{
Obj1.options.remove (0);
}
for (i = 0; i < names.length i + +)
{
Option1 = document.createelement ("option");
option1.innerhtml = Names[i];
Obj1.appendchild (Option1);
}
alert (names);
}
</script>

Background code
AjaxPro.Utility.RegisterTypeForAjax (typeof (Bargain_class)); Page name

===============================ajax Call =====================================
[Ajaxpro.ajaxmethod]
public string link (string name)
{
String text = "";
String sql = "SELECT name from Management_products_class where pid= '" + name + "'";
DataTable dt = linksql.conn (SQL);

for (int i = 0; i < dt. Rows.Count; i++)
{
if (Text = = "")
{
Text = dt. rows[i]["Name"]. ToString ();
}
Else
{
Text + "," + dt. rows[i]["Name"]. ToString ();
}
}
return text;
}