mturk.js

/**
 *  
 *  gup(name) :: retrieves URL parameters if provided
 *
 *  Prepares the page for MTurk on load.
 *  1. looks for a form element with id="mturk_form", and sets its METHOD / ACTION
 *    1a. All that the task page needs to do is submit the form element when ready
 *  2. disables form elements if HIT hasn't been accepted
 *
 **/

// selector used by jquery to identify your form
var form_selector = "#mturk_form";

//  Turkify the captioning page.
$(document).ready(function () {
  // function for getting URL parameters
  function gup(name) {
    name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
    var regexS = "[\\?&]"+name+"=([^&#]*)";
    var regex = new RegExp(regexS);
    var results = regex.exec(window.location.href);
    if(results == null)
      return "";
    else return unescape(results[1]);
  }

  $(document.body).append('<form id="mturk_form"></form>')
  // is assigntmentId is a URL parameter
  if((aid = gup("assignmentId"))!="" && $(form_selector).length>0) {
    // If the HIT hasn't been accepted yet, disabled the form fields.
    if(aid == "ASSIGNMENT_ID_NOT_AVAILABLE") {
	    $('input,textarea,select').attr("DISABLED", "disabled");
    }

    // Add a new hidden input element with name="assignmentId" that
    // with assignmentId as its value.
    var aid_input = $("<input type='hidden' name='assignmentId' value='" + aid + "'>").appendTo($(form_selector));
    var time_spent = $("<input type='hidden' id='timeSpent' name='timeSpent' value='0'>").appendTo($(form_selector));
    var reward_collected = $("<input type='hidden' id='rewardCollected' name='rewardCollected' value='0'>").appendTo($(form_selector));
    var key_presses =  $("<input type='hidden' id='keyPresses' name='keyPresses' value='0'>").appendTo($(form_selector));

    // Make sure the submit form's method is POST
    $(form_selector).attr('method', 'POST');

    // Set the Action of the form to the provided "turkSubmitTo" field
    if((submit_url=gup("turkSubmitTo"))!="") {
      $(form_selector).attr('action', submit_url + '/mturk/externalSubmit');
    }
  }
});