An example of asp.net using Ajax and Jquery to pass parameters from the foreground to the background and return values

1》Front desk

First you need the Jquer package

<script src="js/jquery-1.9.1.js" type="text/javascript"></script>
下面是     <script type="text/javascript">
        $(function () {
            $(&#39;#txtUserName&#39;).blur(function () {
                var username = $(this).val();
                $.ajax({
                    type: "post",
                    contentType: "application/json",//传值的方式
                    url: "WebAjaxForMe.aspx/GetValueAjax",//WebAjaxForMe.aspx为目标文件，GetValueAjax为目标文件中的方法
                    data: "{username:&#39;" + username + "&#39;}",//username 为想问后台传的参数（这里的参数可有可无）
                    success: function (result) {
                        alert(result.d);//result.d为后台返回的参数
                    }
                })
            })
        })
    </script>
//这里是参数的来源
        <input id="txtUserName" type="text" />

2》Backstage

In the background, you must first add the reference of using System.Web.Services;

[WebMethod]//方法前边必须添加 [WebMethod]      
  public static string GetValueAjax(string username)//这个方法需要是静态的方法要用到关键字static       
{
            //在这里可以对传进来的参数进行任何操作           
　　　　return username;    
 }

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