This is the file that the AJAX call loads. The Javascript is included at the bottom (and the library that it references to is called on page load)

file_to_load_by_ajax.php

<div class='admin-box'>
	<h3>Vocabulary</h3>
	<?php echo form_open($this->uri->uri_string(), 'class="form-horizontal"'); ?>
		<fieldset>
            

			<div class="control-group<?php echo form_error('vocab_text') ? ' error' : ''; ?>">
				<?php echo form_label('Vocab text'. lang('bf_form_label_required'), 'vocab_text', array('class' => 'control-label')); ?>
				<div class='controls'>
					<input id='vocab_text' type='text' required='required' name='vocab_text' maxlength='255' value="<?php echo set_value('vocab_text', isset($vocabulary->vocab_text) ? $vocabulary->vocab_text : ''); ?>" />
					<span class='help-inline'><?php echo form_error('vocab_text'); ?></span>
				</div>
			</div>

			<div class="control-group<?php echo form_error('audio_fk') ? ' error' : ''; ?>">
				<label for="file_name" class="control-label"><span id="restart-recording-content" style="display:none;"><a id="restart-recording" href="#"><img style="width:25px; margin-right:10px" src="/assets/images/restart.jpg"></a></span>Record Audio</label>
				<div class='controls'>
					<button id="start-recording">Start Recording</button>
		            <button id="stop-recording" disabled>Stop Recording</button>
		            <div id="audios-container"></div>
				</div>
			</div>

			<div class="control-group<?php echo form_error('image_fk') ? ' error' : ''; ?>">
				<?php echo form_label('Image', 'image_fk', array('class' => 'control-label')); ?>
				<div class='controls'>
		            <label>
		            	<input id="choose_image" type="file" name="files[]"  accept="image/*" title='Click to add Image'>
		            </label>

			    <div class="col-md-6">
				    <div class="panel panel-default">
					    <div class="panel-body demo-panel-files" id='stark-files'>
					   		<!--<span class="demo-note">No image has been uploaded</span>-->
					    </div>
				    </div>
			    </div>
			        <!-- / Right column -->
				</div>
			</div>
        </fieldset>
		<fieldset class='form-actions'>
		<?php

			$data = array(
			              'save'  => 1,
			              'audio_url' => '',
			              'file_name' => '',
			              'text' => '',
			              'image_name' => '',
			              'image_file_name' => '',
			              'direct_url' => ''
			            );

			echo form_hidden($data);

		?>
			<input type='submit' name='save-button' class='btn btn-primary' value="<?php echo lang('vocabulary_action_create'); ?>" />			
		</fieldset>
    <?php echo form_close(); ?>
</div>

<script language="javascript" type="text/javascript">

	$(function() {
		init();
	});
		 function __log(e, data) {
		    console.log ( "\n" + e + " " + (data || ''));
		  }

		  var audio_context;
		  var recorder;

		  alert("script loaded");


		  document.querySelector('#start-recording').onclick = function() {
		      this.disabled = true;
		      recorder && recorder.record();
		      __log('Recording...');
		     document.querySelector('#stop-recording').disabled = false;

		  };
		  
		  document.querySelector('#stop-recording').onclick = function() {
		    recorder && recorder.stop();
		    __log('Stopped recording.');
		    
		    // create WAV download link using audio data blob
		    createDownloadLink();
		    recorder.clear();
		    this.disabled = true;
		  };  
		  
		  document.querySelector('#restart-recording').onclick = function() {
		      this.disabled = true;
		      $('#audios-container').html('');
		      document.querySelector('#start-recording').disabled = false;
		      document.querySelector('#stop-recording').disabled = false;
		      $('#start-recording').show();
		      $('#stop-recording').show();
		  };



		  function startUserMedia(stream) {
		  	alert("inside startusermedia");
		    var input = audio_context.createMediaStreamSource(stream);
		    __log('Media stream created.');
		    recorder = new Recorder(input);
		    __log('Recorder initialised.');

		  }


		  function createDownloadLink() {

		    var audio = document.createElement('audio');
		    $('#restart-recording-content').show();

		    $('#start-recording').hide();
		    $('#stop-recording').hide();

		    document.querySelector('#start-recording').onclick = function() {
		        this.disabled = true;
		        recorder && recorder.record();
		        __log('Recording...');
		    };
		    
		    recorder && recorder.exportWAV(function(blob) {
		    
		        var fileType = 'audio'; // or "audio"
		        var fileName = 'temp-ajax-audio.wav';  // or "wav" or "ogg"
		        var cookie = getCookie('ci_csrf_token');

		        audiosContainer.appendChild(audio);
		        audio = mergeProps(audio, {
		            controls: true,
		            src: URL.createObjectURL(blob)
		        });

		        audio.play();

		        var formData = new FormData();
		        formData.append(fileType + '-filename', fileName);
		        formData.append(fileType + '-blob', blob);
		        formData.append('ci_csrf_token', cookie);

		        $.ajax({
		            url : "/admin/content/audio/audio_upload",
		            type: "POST",
		            data : formData,
		            contentType: false,
		            processData: false, 
		            success: function(data, textStatus, jqXHR)
		            {
		                document.querySelector('#start-recording').disabled = false;
		                alert(result.file_path);
		                var result = jQuery.parseJSON(data);
		                $("#file_name").val(result.file_name);
		                $("#audio_url").val(result.file_path);
		                

		            },
		            error: function (jqXHR, textStatus, errorThrown)
		            {
		                alert("Oops something happened." + " --- ");
		            }
		        });
		    });
		  }

		  function mergeProps(mergein, mergeto) {
		        mergeto = reformatProps(mergeto);
		        for (var t in mergeto) {
		            if (typeof mergeto[t] !== 'function') {
		                mergein[t] = mergeto[t];
		            }
		        }
		        return mergein;
		    }

		    function reformatProps(obj) {
		        var output = {};
		        for (var o in obj) {
		            if (o.indexOf('-') != -1) {
		                var splitted = o.split('-');
		                var name = splitted[0] + splitted[1].split('')[0].toUpperCase() + splitted[1].substr(1);
		                output[name] = obj[o];
		            } else output[o] = obj[o];
		        }
		        return output;
		    }

		  function getCookie(key) {
		      var keyValue = document.cookie.match('(^|;) ?' + key + '=([^;]*)(;|$)');
		      return keyValue ? keyValue[2] : null;
		  }
		  
		  // below function via: http://goo.gl/B3ae8c
		  function bytesToSize(bytes) {
		     var k = 1000;
		     var sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
		     if (bytes === 0) return '0 Bytes';
		     var i = parseInt(Math.floor(Math.log(bytes) / Math.log(k)),10);
		     return (bytes / Math.pow(k, i)).toPrecision(3) + ' ' + sizes[i];
		  }
		  
		  // below function via: http://goo.gl/6QNDcI
		  function getTimeLength(milliseconds) {
		      var data = new Date(milliseconds);
		      return data.getUTCHours()+" hours, "+data.getUTCMinutes()+" minutes and "+data.getUTCSeconds()+" second(s)";
		  }

		  var audiosContainer = document.getElementById('audios-container');
		  var index = 1;

		  function init() {
		    try {
		      // webkit shim
		      window.AudioContext = window.AudioContext || window.webkitAudioContext;
		      navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia;
		      window.URL = window.URL || window.webkitURL;
		      
		      audio_context = new AudioContext;
		      __log('Audio context set up.');
		      __log('navigator.getUserMedia ' + (navigator.getUserMedia ? 'available.' : 'not present!'));
		    } catch (e) {
		      alert('No web audio support in this browser!');
		    }
		    
		    if(navigator.getUserMedia) { 
		    	alert("condition true");
			    navigator.getUserMedia({audio: true}, startUserMedia, function(e) {
			      __log('No live audio input: ' + e);
			    });		    	
			} else {
			      __log('fail ');

			}

		  }

</script>