There is no type or namespace name "Script" in the Namespace "system.web" (is the assembly reference missing?)

Some information on the web said that the right mouse button on the item, add reference →. Net→system.web.entensions can do it.

In fact, many times on the Add Reference window in the project, System.Web.Entensions is not found at all.

Try to add configuration information (note <assemblies> Two lines of configuration ) under <system.web> in Web. config to solve the problem perfectly. Such as:

  <system.web>  <!--Set compilation debug= "True" to insert the debug symbol into the compiled page.        However, because this affects performance, this value is set to true only during development.  -  <compilationDebug= "true">   <Assemblies>        <AddAssembly= "System.Web.Extensions, version=1.0.61025.0, Culture=neutral, publickeytoken=31bf3856ad364e35" />        <AddAssembly= "System.Web.Extensions.Design, version=1.0.61025.0, Culture=neutral, publickeytoken=31bf3856ad364e35" />      </Assemblies>    </compilation>

There is no type or namespace name "Script" in the Namespace "system.web" (is the assembly reference missing?)