可以用extjs6连接电脑摄像头并且具有拍照和录像功能，还可以点击回放的例子

各种 JavaScript 框架都可以连接电脑摄像头并实现拍照和录像功能，包括 ExtJS6。以下是一个使用 ExtJS6 实现拍照和录像的例子：

Ext.application({
name: 'MyApp',
launch: function() {
var video = Ext.create('Ext.panel.Panel', {
title: 'Video',
width: 640,
height: 480,
html: '<video id="video" width="640" height="480" autoplay></video>',
renderTo: Ext.getBody()
});

var canvas = Ext.create('Ext.panel.Panel', {
title: 'Canvas',
width: 640,
height: 480,
html: '<canvas id="canvas" width="640" height="480"></canvas>',
renderTo: Ext.getBody()
});

var buttonPanel = Ext.create('Ext.panel.Panel', {
title: 'Controls',
width: 640,
height: 50,
layout: {
type: 'hbox',
align: 'middle',
pack: 'center'
},
items: [{
xtype: 'button',
text: 'Start',
handler: function() {
navigator.mediaDevices.getUserMedia({
video: true
}).then(function(stream) {
var videoElement = document.getElementById('video');
videoElement.srcObject = stream;
videoElement.play();
});
}
}, {
xtype: 'button',
text: 'Stop',
handler: function() {
var videoElement = document.getElementById('video');
videoElement.pause();
videoElement.srcObject.getTracks()[0].stop();
}
}, {
xtype: 'button',
text: 'Snapshot',
handler: function() {
var videoElement = document.getElementById('video');
var canvasElement = document.getElementById('canvas');
var context = canvasElement.getContext('2d');
context.drawImage(videoElement, 0, 0, canvasElement.width, canvasElement.height);
}
}, {
xtype: 'button',
text: 'Record',
handler: function() {
var videoElement = document.getElementById('video');
var mediaRecorder = new MediaRecorder(videoElement.srcObject);
var chunks = [];

mediaRecorder.ondataavailable = function(event) {
chunks.push(event.data);
};

mediaRecorder.onstop = function(event) {
var blob = new Blob(chunks, {
type: 'video/mp4'
});
var url = URL.createObjectURL(blob);
var a = document.createElement('a');
a.href = url;
a.download = 'video.mp4';
a.click();
};

mediaRecorder.start();
}
}],
renderTo: Ext.getBody()
});
}
});

至于点击回放的例子，我不太清楚你具体想要实现什么功能，可以提供更多的信息吗？