问如何获取javascript代码的父div (纯js)？

EN

<div id="a">
    <div id="b">
        <script type="text/javascript">
            var MyDiv1 = GetMyOwnDiv();
        </script>
    </div>
    <div id="c">
        <script type="text/javascript">
            var MyDiv2 = GetMyOwnDiv();
        </script>
    </div>
</div>

//---Global loaded script in HEAD---
function LoadAsyncScript(){
    //.....
    var TScriptData = xmlhttp.responseText;
    var TAppID = G_UNIQUEID;
    var TScript = document.createElement('script');
    TScript.setAttribute('type', 'text/javascript');
    TScript.innerHTML = TScriptData;
    document.getElementById('div_main').insertAdjacentHTML('beforeend', '<div id="_' + TAppID + '_app" style=""></div>');
    var TApp = document.getElementById('_' + TAppID + '_app');
    TApp.dataset['appid'] = TAppID;
    TApp.appendChild(TScript);
    //.....
};

function CloseApp(V_AppID){
    var TMyAppDiv = document.getElementById('_' + V_AppID + '_app');
    TMyAppDiv.removeChild(TMyAppDiv);
};
//---END OF Global loaded script in HEAD---


//Async loaded and "appendChild" script part
function OnClick_Callback(){
    var TMyDiv = GetMyDivOfThisFunction();
    CloseApp(TMyDiv.dataget['appid']);
};
//......