Asp.net codebehind from javascript?

Is it possible to call asp.net codebehind function from javascript in vs2008?

My problem is, I have two codebehind methods, one is for some validation and it will return true or false. This method will be called when user click submit button and if return value is true, I want to call javascript function for confirm(confirm dialog box) and if it is OK,

I will call another codebehind method for update. If validation method return false or javascript cancel, nothing changes. Now, my code is like this:

<script language="javascript" type="text/javascript">
function Confirm()
{
    var checkUpdate = confirm("Do you wish to save changes?");
    if (checkUpdate)
    {
        return true;
    }
    else 
    {
        return false;
    }
}

protected void Button1_Click(object sender, EventArgs e)
{
    if(CheckValidate())
    {
        string script = "<SCRIPT LANGUAGE=开发者_如何学编程'JavaScript'> ";
                    script += "Confirm()";
                    script += "</SCRIPT>";
                    Page.RegisterStartupScript("ClientScript", script);

        //If Javascript Ok Call Update,Otherewise,nothing;  
    }
}

private boolean CheckValidate()
{
    return boolean;
}

private void UpdateData()
{
    //Update;   

 }

However, it goes immediately to update method and after updating, javascript confirmation box comes out.

How i change to get right sequence? please give me the right way.

Yes by making use of PageMethods you can call the codebehind methods from javascript.

Check this link for more detail about pagemethods : http://aspalliance.com/1922_PageMethods_In_ASPNET_AJAX

To call a server side method on a client side event you need to do the following:

1- Create the server side method:

void DoSomething(...) { ... }

2- Implement the System.Web.UI.IPostBackEventHandler.RaisePostBackEvent which take one string argument (You can assign the name to the value of this argument).:

public void RaisePostBackEvent(string eventArgument) 
{
        DoSomething(...);
}

3- Write a script to trigger post back:

function TriggerPostBack(control, arg){
    __doPostBack(control, arg);
}

4- Call the PostBack trigger function when needed:

<a .... onclick="TriggerPostBack('control', 'arg')" .. /> 

In your case, why don't you use OnClientClick function of the button to call your javascript function?

Regards, S Mukherjee.