webrtc,人脸拍照小功能

  
  
      
          
          
		
      
      
         
		
		拍照
		 

      
  

function hasUserMedia(){//判断是否支持调用设备api，因为浏览器不同所以判断方式不同哦  
	return !!(navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia);  
}  
if(hasUserMedia()){  
	//alert(navigator.mozGetUserMedia)  
	navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;  
	var video=document.querySelector("video");  
	var canvas=document.querySelector("canvas");
	var streaming = false;
	navigator.getUserMedia({  
		video:true,//开启视频  
		audio:false//先关闭音频，因为会有回响，以后两台电脑通信不会有响声  
	},function(stream){//将视频流交给video  
		video.src=window.URL.createObjectURL(stream);   
		streaming = true;
	},function(err){  
		console.log("capturing",err)  
	});  
	document.querySelector("#capture").addEventListener("click",function(event){
		if(streaming){
			//alert(video.clientHeight)
			//canvas.width = video.clientWidth;
			//canvas.height= video.clientHeight;
			canvas.width = 800;
			canvas.height = 800;
			var context = canvas.getContext('2d');
			context.drawImage(video,20,20)
		}
	})
}else{  
	alert("浏览器暂不支持")  
}