function sharescreen(){
let displayMediaOptions = {video: true, audio: false};
navigator.mediaDevices.getDisplayMedia(displayMediaOptions)
.then(function(stream){
video_el.srcObject = stream;
})
}
function sharescreen(){
let displayMediaOptions = {video: true, audio: false};
navigator.mediaDevices.getDisplayMedia(displayMediaOptions)
.then(function(stream){
video_el.srcObject = stream;
})
}