Invoke server side method using XMLHttpRequest

how can i directly call my own server side function using XMLHttpRequest.

suppose i have one static webmethod in my aspx file then how can i call it by XMLHttpRequest. what header info i need to pa开发者_如何转开发ss to asp.net engine and as a result asp.net engine can invoke my method and return the response back in the out going stream.

this way i need to call my server side method

    <script type="text/javascript">
var request;

// A
// Here is the new function that is called when the user submits the form.
// This example uses POST.
function submitCallback() {
    var inputValue = document.getElementById("SearchInput").value;
    var sendStr = "name=" + inputValue;
    request = new XMLHttpRequest();

    // B
    // Specify the POST method and send it.
    request.open("POST", "Default.aspx/Getdata");
    request.onreadystatechange = readyCallback;
    request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    request.setRequestHeader("IsLookup", "true");
    request.send(sendStr);
}
</script>

please guide me....thanks

I believe you are probably referring to ASP.NET Page Methods when you say One static webmethod in my aspx file. ASP.NET page methods (or web services for consumption in JS) uses JSON serialization for i/p and o/p. So you need to set JSON as the content type for the request and actually send the JSON string in the body i.e.

...
var sendStr = "{name:" + inputValue + "}";
...
request.setRequestHeader("Content-Type", "application/json");
...
request.send(sendStr);

Further, I will suggest you to use jquery or ASP.NET generated proxies (by ScriptManager) instead of directly coding against XmlHttpRequest. See this article for how to use jquery for calling Page methods.

I think, the easiest way will be usage of jQuery for ajax requests: http://api.jquery.com/category/ajax/