not able to access iframe contents using jquery or javascript

Your issue of not able to access iframe elements using jQuery or javascript is related to same origin policy, that's why you are getting the permission error.

If the <iframe> is from the same domain, the elements are accessible using jQuery like

$("#iFrame").contents().find("#DivID").AnyFunction();

Or you can try this method which triggers after loading of iFrame gets complete

$(document).ready(function(){
//executes once the iframe has finished loading
 $("#iframeID").ready(function () { 
       $('#Selector', frames['nameOfMyIframe'].document).functionStuff();
    });
    
});

Above solution will resolve your loading issue, but it will not resolve cross-domain issue(permission error)

You can try this code also

$(document).ready(function(){
    $('#IfOfFrame').load(function(){
        $('#IfOfFrame').contents().find('body').html('Your new HTML Here');
    });
});

Try using 

var $iframe = $("#iframeID").contents();
$iframe.find('selector');

But your iframe content must be from same origin otherwise you will get error permission denied type error.