Android : Memory Getting Piled PhoneGap App

I have a PhoneGap / JQuery MObile App which fetches data from server thru Ajax and displays it as a list. With each Ajax fetch the Memory occupied by App increases by about 10 MB. For the first fetch it might be OK as it fetches a large number of records (around 700). However, for subsequent calls my understanding is that it should reuse the memory instead of piling up another 10 MB each time. I have used .off() to release event handlers in case they were holding the memory but no success.

Here is the main page Div where the output is displayed:

<div data-role="content"  class="MainContent"  style="overflow:hidden; padding-top: 0px;">
    <ul data-divider-theme="b" data-role="listview" data-inset="true" class="MainMenu">

    </ul>

And this is the Javascript code that fetches the data from server and displays in the above div.

AjaxFile = "mydomai.com/ajax.php";
$.get(AjaxFile, function (AjaxData) {

    $( ".PL" ).off();
    $(".MainMenu").off();
    $(".MainContent").off();

    AjaxData = '<li class="MainMenuList" data-role=list-divider>' + gTitle + AjaxData;
    $(".MainMenu").empty();
    $(".MainMenu").html(AjaxData);
    $(".MainMenu").listview('refresh');
    window.scrollTo(0, 0);
    $.mobile.loading('hide');

    HighlightRow(gCurrentFile);
    $(document).ready(function () {
        $(".PL").click(function () {
            if ( !$(this).hasClass("BTitleRow") )
            {
                $(".PL").removeClass("RowHighlight");
                $(this).addClass("RowHighlight");
                OpenNewLink($(this).attr('name'));
            }
        });
    });

});

AjaxData = null;
return;

Can someone please tell me how can I free up the memory and ensure that the same memory is reused instead of piling up more and more memory.

Many Thanks.