Call code behind method from JavaScript in asp.net

There are ways to call a web service method JavaScript, for more detail you can see how to retrieve data from database using JavaScript in asp.net, but is there any way to call a normal method from JavaScript? And the answer is No; show how we can call a code behind method from JavaScript, let’s see this with code

Add following HTML on page:

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="True" />

<div>
   <div>Enter your name:</div>
   <div> 
       <asp:TextBox ID=”txtName” runat=”server” />
  </div>
  <div> 
       <asp:TextBox ID=”txtMessage” runat=”server” />
  </div>
  <div> 
       <asp:Button ID=”btnSave” runat=”server” Text=”Save”
          OnClientClick=”return CallCodeBehindMethod();” />
  </div>
</div>

Now time to adjust our code behind so we can call it from JavaScript, wee need to use System.Web.Services so add it in our code behind file

using System.Web.Services;

Whatever method we need to call from JavaScript, add WebMethodattribute to that method and that will easily be called by javaScript

[WebMethod]
public String GetName()
{
    if(DateTime.Now.Hour < 12)
      return "Good morning, " + txtName.Text;
   else if(DateTime.Now.Hour < 16)
      return "Good after noon, " + txtName.Text;
   else 
      return "Good evening, " + txtName.Text;  
}

Now we will call GetName from JavaScript, so add the following JavaScript to the page:

function CallCodeBehindMethod()
{
    pageName.GetName(OnSuccess, OnFailed);
}

function OnSuccess(val)
{
   if(val)     
       document.getElementById('txtMessage').value = val;
}
function OnSuccess(error)
{
   if(error)     
       document.getElementById('txtMessage').value = error;
}

As you can see we have not used web service but we changed a method to web method so it can be called from JavaScript but without converting a method into web method we can not call any code behind method from JavaScript.

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