Untitled

var iframe = document.getElementsByTagName('iframe')[0]; // or [1] depending on which iframe contains the dropdown
var iframeDocument = iframe.contentDocument || iframe.contentWindow.document;

var select = iframeDocument.getElementById('FromCountry');
if (select) {
    for (var i = 0; i < select.options.length; i++) {
        if (select.options[i].value === 'VN') { // Vietnam code
            select.selectedIndex = i;
            console.log("Country selected:", select.options[i].text);
            break;
        }
    }
} else {
    console.log('Dropdown not found in the iframe.');
}