send an http request without XHR in an event handler

Question

How to send an http request with either post/get method using javascript as an eventhandler? Thanks! Paul

Answer 1

Okay, you don't want to use Ajax. You can use an event handler to submit a form!

<a href='#' onclick='cow_submit("zoodle")'>send</a>
<form method='post' id='formie' action='find_some_action.php'>
  <input type='hidden' id='snoutvar' name='snoutvar' value='snout'>
</form>

<script>
function cow_submit(a_var_to_set){
  var plip=document.getElementById('formie');
  var snout=document.getElementById('snoutvar');
  snout.value=a_var_to_set;
  plip.submit();
  }

See https://developer.mozilla.org/en/DOM/form

Answer 2

use XmlHttpRequest

sample code:

var client = new XMLHttpRequest();
client.onreadystatechange = handler;
client.open("GET", "test.xml");
client.send();

function handler()
{
   // your handler
}

Answer 3

You can use XMLHttpRequest for sending request from javascript

Sending GET request

var url = "get_data.php";
var params = "lorem=ipsum&name=binny";
http.open("GET", url+"?"+params, true);
http.onreadystatechange = function() {//Call a function when the state changes.
    if(http.readyState == 4 && http.status == 200) {
        alert(http.responseText);
    }
}
http.send(null);

Sending POST request

var url = "get_data.php";
var params = "lorem=ipsum&name=binny";
http.open("POST", url, true);

//Send the proper header information along with the request
http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http.setRequestHeader("Content-length", params.length);
http.setRequestHeader("Connection", "close");

http.onreadystatechange = function() {//Call a function when the state changes.
    if(http.readyState == 4 && http.status == 200) {
        alert(http.responseText);
    }
}
http.send(params);

And don't forget to encode parameters using encodeURIComponent for param value encoding in case of user input

e.g.

params="paramName="+encodeURIComponent(paramValue);

Answer 4

The standard class for doing this is XmlHttpRequest, but it's not universally supported. On some browsers you have to use ActiveXObject("Microsoft.XMLHTTP") instead.

Look into the jQuery system which provides HTTP download (AJAX style) methods regardless of the underlying browser APIs (hence avoiding a lot of the code shown in Tzury's answer).

The jQuery AJAX documentation is at http://docs.jquery.com/Ajax

Answer 5

You should try to add atring in a hidden field and then call the form.submit() to submit your form into the page define in action.

<script type="text/javascript">
  function doTestFormSubmit(yourString) {
    document.getElementById("myString").value=myString;
    document.getElementById("testForm").submit();
  }
</script>
<form name="testForm" id="testForm" action="yourDesiredPage.php" method="post">
   <input type="hidden" name="myString" id="myString" value=""/>
</form>

Answer 6

Ajax Tutorial (http://code.google.com/edu/ajax/tutorials/ajax-tutorial.html)

var obj;

function ProcessXML(url) {
  // native  object

  if (window.XMLHttpRequest) {
    // obtain new object
    obj = new XMLHttpRequest();
    // set the callback function
    obj.onreadystatechange = processChange;
    // we will do a GET with the url; "true" for asynch
    obj.open("GET", url, true);
    // null for GET with native object
    obj.send(null);
  // IE/Windows ActiveX object
  } else if (window.ActiveXObject) {
    obj = new ActiveXObject("Microsoft.XMLHTTP");
    if (obj) {
      obj.onreadystatechange = processChange;
      obj.open("GET", url, true);
      // don't send null for ActiveX
      obj.send();
    }
  } else {
    alert("Your browser does not support AJAX");
  }
}


function processChange() {
    // 4 means the response has been returned and ready to be processed
    if (obj.readyState == 4) {
        // 200 means "OK"
        if (obj.status == 200) {
            // process whatever has been sent back here:
        // anything else means a problem
        } else {
            alert("There was a problem in the returned data:\n");
        }
    }
}