Apex Stylings Hide the buttons loaded from the vf page

I have an ifram url which i am using in vf page, but when i preview the vf page i should hide the buttons.I have tried the below one,can anyone help me to reach out this.

<apex:page >
    <iframe id="defframe" src= "https://quikforms.com/viewform/zq9M-TfUuLT6FWR" style="height:100%; width:100%; border:none"/>
    <script type="text/javascript">
    window.onload = function() {
        setTimeout(callfunction(), 1000000);
    };
    function callfunction(){
        var iframe = document.getElementById("defframe");
        alert('iframe id'+iframe);
        alert('function called');
        alert('AAAAAA'+document.getElementById('btnSave'));
        var savebuttonId = document.getElementById('btnSave').style.display = none;
        var printButtonId = document.getElementById('btnPrint').style.display = none;
    
}; 
</script>
</apex:page>