c# functions call through javascript

You may try this :

Page.ClientScript.RegisterStartupScript(this.GetType(),"Call my function","MyFunction()",true);

for more Details visit here....
http://stackoverflow.com/questions/5731224/calling-javascript-function-from-codebehind[^]
http://www.c-sharpcorner.com/UploadFile/abhikumarvatsa/calling-an-Asp-Net-C-Sharp-method-web-method-using-javascript/[^]

It's quite straightforward using the __doPostBack call from Javascript.

In the Page_Load function in your code behind, put:

protected void Page_Load(object sender, EventArgs e)
{
    // ensure page always includes the __doPostBack function
// (best to put this in your Master Page, if you have one)
    Page.ClientScript.GetPostBackEventReference(this, string.Empty);

// now test if a postback event occurred
if (Page.IsPostBack)
{
            // postback occurred, so determine which function name was called
            switch (Request.Form["__EVENTTARGET"])
            {
                case "myProcedure1":
                    {
                        // go and call your function
                        doMyProcedure1(Request.Form["__EVENTARGUMENT"]);

                        break;
                    }
    }
}
}

Then further down in your code behind, create the C# function you wish to call:

protected void doMyProcedure1(String someVar)
{
// do your function code here
String passedVar = someVar;
}

Then finally in your Javascript, do the postback that calls the C# function:

function callMyFunction()
{
__doPostBack('myProcedure1', 'some string');
}