What are the implementation methods of AJAX secondary linkage?

This time I will bring you the implementation methods of AJAX second-level linkage, and what are theprecautionsfor the implementation of AJAX second-level linkage. The following is a practical case, let's take a look.

BackendHandler.ashx

<%@ WebHandler Language="C#" Class="Handler" %> using System; using System.Web; using System.Data; public class Handler : IHttpHandler { Common coObj = new Common(); public void ProcessRequest(HttpContext context) { if (context.Request.Params["n"] != null) { string num = context.Request.Params["n"].ToString(); context.Response.ContentType = "text/plain"; string str = "select * from address where a_num2=" + num; DataTable dt = coObj.GetTable(str); string json = JSONHelper.DataTableToJSON(dt); context.Response.Write(json); } } public bool IsReusable { get { return false; } } }

frontend dropdownlist.html

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website !

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