$(document).ready(function(){

var iframe = $('#vid1');
var button = $('#mute-toggle');

var flag = 0;
$(button).on('click', function() {
if (flag == 0){
// unmute
flag = 1;
$(iframe)[0].contentWindow.postMessage('{ "event": "command", "func":
"unMute", "method":"setVolume", "value":0}',"*");
$(this).find('.yotube-volume-button').removeClass('fa-volume-
off').addClass('fa-volume-up');
}
else {
// mute
flag = 0;
$(iframe)[0].contentWindow.postMessage('{ "event": "command", "func":
"mute", "method":"setVolume", "value":0}',"*");
$(this).find('.yotube-volume-button').removeClass('fa-volume-
up').addClass('fa-volume-off');
}
});

});