How to pass parameter from javascript to code behind?

Question

i tried pass parameter from jscript to code behind, but it don't work. My code:

[C#]

[WebMethod]
public static String sendEmail(String str)
{
     ...
     msg.body = str;
     ...
     return str;
}

[jscript]

If i use function alert, it return null

function onOkClickButton()
{
    var content = "Hello";
    alert("<%=sendEmail(" + content + ")%>");
}

if i use PageMethod, my email's body is null

<asp:ScriptManager enablePageMethods="true"></asp:ScriptManager> 
function onOkClickButton()
{
    var content = "Hello";
    PageMethods.sendEmail(content, onSuccess, onError);
}
function onSuccess(text)
{
    alert(text)
}

function onError(text)
{
    alert(text)
}

Can you help me?

Answer 1

jQuery ajax would be the easiest method, IMO:

function onOkClickButton()
{
    var content = "Hello";

    $.ajax({
      type: "POST",
      url: "urlToPageHostingSendEmail.aspx/sendEmail",
      data: { str: content }
    }).success(function( msg ) {
      alert( msg );
    });
}

Answer 2

You could use jquery to call your page method:

call page method without script manager from jquery

or

http://encosia.com/using-jquery-to-directly-call-aspnet-ajax-page-methods/

Also have a look at this video:

http://www.highoncoding.com/Articles/430_Calling_Page_Methods_Using_JQuery_and_Returning_JSON_Result.aspx