Javascript function not getting called from HTML file

Question

I am new to phonegap and working on a phonegap iOS app.I am trying to call a JavaScript function from HTML class, but strangely it is not getting called. The same works fine with android codebase.

Here is my HTML class code:

<script language="javascript" type="text/javascript"></script>
<!--<script type="text/javascript" charset="utf-8" src="js/cordova.js"></script>-->
<script type="text/javascript" charset="utf-8" src="pages/VoiceRecord.js"></script>

<div data-role="page" id="VoiceRecord">
    <div data-role="header"  data-position="fixed" class="header">
        <a onclick='OpenLeftPanel();' data-theme="a" ><img class="iconimg" src="images/lines_menu.png" data-theme="none"/></a>
        <img class="headlogo" src="images/logo_inner.png"/>
        <a onclick='OpenRightPanel();' data-theme="none" ><img class="iconimg" src="images/profile_menu.png"/></a>
    </div>

    <div data-role="main" class="ui-content" id="VoiceRecordnotes">
        <label id="labe_id">Recording Audio... </label><label id="audio_position"> </label>
        <button id="media" data-inline="true" class="ui-btn-a ui-mini" type="button" value="" onclick="recordAudio()">Record</button>
        <button id="stop" data-inline="true" class="ui-btn-a ui-mini" type="button" value="" onclick="stop()" disabled>Stop Recording</button>
    </div>
</div>

<script>
    function recordAudio(){
        alert("indside recordAudio in .htm");

        document.getElementById("labe_id").style.visibility="visible";
        document.getElementById("audio_position").style.visibility="visible";

        startAudioRecording();
        $('#media').attr('disabled', 'disabled');
        $("#stop").removeAttr('disabled');
    }

function stop(){
    alert("inside stop in .htm");
    $('#stop').attr('disabled', 'disabled');
    $("#media").removeAttr('disabled');
    stopAudioRecording();
    navigate('helpline');
}

</script>

and my JS class code is:

function startAudioRecording(){
    alert ("recordAudio in js");
        var user = getCurrentUser();
        alert("user" +user);
        var username=user.userId;
        var phoneno=user.phone_no;
    cordova.exec(succesCallBack, erorCallBack,'AudioRecording','recordAudio',[{"username":username,"phoneno":phone_no}]){
    };

I have included my JS file in index.html. When I run my HTML file in browser and try to jump to my JS file it opens a blank file in safari.

Can anyone guide me with this?