how to call OnTextChanged in asp:TextBox when press any key

I used an asp:Textbox as a search box on the ascx page. Now it works when I press enter after inputting my text. I want to change it to smart search. (when I press a key, the OnTextChanged should call to code behind the function without clicking anywhere or pressing enter key) please help me to achieve this. Thank you

<asp:TextBox ID="SearchBox" runat="server" placeholder="Search" AutoPostback="true" OnTextChanged="SearchBox_TextChanged" ></asp:TextBox>

code behind in ascx page:

protected void SearchBox_TextChanged(object sender, EventArgs e)
{           
     // searching
}

you can use the onkeyup event of the TextBox to call JavaScript function which makes AJAX request to the server to perform the search, to do so, add

onkeyup="search()"

to your TextBox:

<asp:TextBox ID="SearchBox" runat="server" placeholder="Search" onkeyup="search()"></asp:TextBox>

Then call the

search()

function

Javascript:

function search() 
{
   var searchTerm = $('#<%=SearchBox.ClientID%>').val();
   $.ajax({
       type: "POST",
       url: "YourPage.aspx/SearchBox_TextChanged",
       data: "{searchTerm: '" + searchTerm + "'}",
       contentType: "application/json; charset=utf-8",
       dataType: "json",
       success: function (response) {
           // Handle success response
       },
       error: function (xhr, status, error) {
           // Handle error response
       }
   });
 }

and finally perform your search in server side and return result:

C#:

[System.Web.Services.WebMethod]
public static string SearchBox_TextChanged(string searchTerm)
{
   // Perform search and return result as a JSON object
   return JsonConvert.SerializeObject(searchResults);
}