How Can I Disable A Button In I-Frame After First Click

function DisableSubmitBtn() {

    alert('hi1');
    document.getElementById('framenewquery').src = 'frmimgupload.aspx?qid=0';
    var gBrowserName = navigator.appName;
    alert(gBrowserName);
   // var gBrowserVer = parseInt(navigator.appVersion);
    if (gBrowserName == 'Netscape') {
        alert("hi3");
        // alert(document.getElementById("framenewquery").src);
        var iframe = document.getElementById('framenewquery');
        alert(iframe);
        var iframeDocument = iframe.contentDocument || iframe.contentWindow.document;
        alert(iframeDocument);
        var iframeContent;

        if (iframeDocument) {
            //iframeContent = iframeDocument.getElementById('btnsubmit');

            iframeDocument.getElementById('btnsubmit').disabled = true;
           // iframeContent.hasOwnProperty() = false;
        }