Call codebehind server code from javascript

to execute the code written in code behind (c#, vb.net). we need to know that the exists on server, not at client. so it is needed to make a postback to reach the code.

to avoid full postback we can use AJAX.



put the code below in your .aspx.cs file

private void Page_Load(object sender, System.EventArgs e)

{

Ajax.Utility.RegisterTypeForAjax(typeof(WebForm1));

DropDownList1.Attributes.Add("onchange","CallBack();");

}

[Ajax.AjaxMethod()]

public int ServerSideAdd(int firstNumber,int secondNumber)

{

return firstNumber + secondNumber;

}

Put the given below code in your aspx file

< script language="javascript" >

function CallBack()

{

val1=document.getElementById('txtValue1').value;

val2=document.getElementById('txtValue2').value;

WebForm1.ServerSideAdd(val1,val2, ServerSideAdd_CallBack);

 

}

function ServerSideAdd_CallBack(response)

{

alert(response.value);

}

< /script >

< body MS_POSITIONING="GridLayout" >

< form id="Form1" method="post" runat="server" >

< INPUT onclick="CallBack()" type="button" value="Button" runat="server" >

< asp:dropdownlist id="DropDownList1" style="Z-INDEX: 101; LEFT: 224px; POSITION: absolute; TOP: 48px"

runat="server" >

< asp:ListItem Value="Rajesh" >Amit< /asp:ListItem >

< asp:ListItem Value="Rolen" >Ajay< /asp:ListItem >

< asp:ListItem Value="JSJodha" >Arun< /asp:ListItem >

< asp:ListItem Value="Mukesh" >Ravi< /asp:ListItem >

< /asp:dropdownlist >< asp:button id="Button1" style="Z-INDEX: 102; LEFT: 280px; POSITION: absolute; TOP: 160px" runat="server"

Text="Button" >< /asp:button >

< asp:TextBox id="txtValue" style="Z-INDEX: 103; LEFT: 304px; POSITION: absolute; TOP: 88px" runat="server" >< /asp:TextBox >

< asp:TextBox id="txtValue1" style="Z-INDEX: 104; LEFT: 312px; POSITION: absolute; TOP: 232px"

runat="server" >< /asp:TextBox >

< asp:TextBox id="txtValue2" style="Z-INDEX: 105; LEFT: 520px; POSITION: absolute; TOP: 200px"

runat="server" >< /asp:TextBox >< /form >

< /body >