how to pass dynamic url into iframe?

how to pass dynamic url into iframe?

JavaScript

function youtube_parser(){

    var url = "https://www.youtube.com/embed/w0FzELkRReM";
    var regExp = /^.*((youtu.be\/)|(v\/)|(\/u\/\w\/)|(embed\/)|(watch\?))\??v?=?([^#\&\?]*).*/;
    var match = q.match(regExp);
    var embed = (match&&match[7].length==11)? match[7] : false;
    var common = 'https://www.youtube.com/embed/;'
    
    alert(common.concat(embed))
    
}

youtube_parser();