为了更好的进行封装，每个实现不同功能的js代码应该有自己的js文件，这样如果一个网页中引用了多个js文件，如下

<script type="text/javascript" src="limit.js"></script>
<script type="text/javascript" src="select.js"></script>
<script type="text/javascript" src="rating.js"></script>

1.新建一个HttpHandler

public class Handler1 : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {//原文链接：blog.csdn.net/bluceyoung
            string[] js = context.Request.Url.LocalPath.Substring(1, context.Request.Url.LocalPath.Length - 5).Split('.');
            StringBuilder sb = new StringBuilder();
            foreach (string j in js)
            {
                sb.Append(ReadFile(j+".js"));                
            }
            context.Response.Write(CompressStr(sb));
        }

        private string ReadFile(string fileName)
        {
            string directory = @"D:\SRC\bluceyoung\";
            if (!File.Exists(directory + fileName))
            {
                return "";
            }
            string result;
            using (FileStream fs = new FileStream(directory + fileName, FileMode.Open))
            {
                using (StreamReader sr = new StreamReader(fs))
                {
                    result = sr.ReadToEnd();
                }
            }
            return result;
        }

        private string CompressStr(StringBuilder sb)
        {
            while (true)
            {
                int length = sb.Length;
                sb.Replace("  ", " ");
                if (length == sb.Length)
                    break;
            }
            sb.Replace("\r\n", "").Replace("\t", "").Replace("; ", ";").Replace(" }", "}").Replace("} ", "}").Replace(" ;", ";").Replace(" {", "{").Replace("{ ", "{");
            return sb.ToString();
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }

2.配置文件中添加节点

<configuration>
    <system.web>
        <compilation debug="true" targetFramework="4.0" />
      <httpHandlers>
        <add path="*.jsx" verb="*" type="BluceYoung.Handler1"/>
      </httpHandlers><!--原文博客：blog.csdn.net/bluceyoung -->
    </system.web>
</configuration>

3.页面调用

<script src="limit.select.rating.jsx" type="text/javascript"></script>