HTML5调用电脑摄像头拍照

前台代码：

<div id="contentHolder">       
 <video id="video" width="320" height="320" autoplay>
</video>       
 <button id="snap" style="display:none"> 拍照</button>        
<canvas style="display:none" id="canvas" width="320" height="320">
</canvas> 
   </div>

JS代码：

<script>    //这段代 主要是获取摄像头的视频流并显示在Video 签中           
window.addEventListener("DOMContentLoaded", function () {            
   var canvas = document.getElementById("canvas"),              
     context = canvas.getContext("2d"),                
   video = document.getElementById("video"),          
         videoObj = { "video": true },             
      errBack = function (error) {           
            console.log("Video capture error: ", error.code);    
               };               
    //navigator.getUserMedia这个写法在Opera中好像是navigator.getUserMedianow       
        if (navigator.getUserMedia) {     
              navigator.getUserMedia(videoObj, function (stream) {
                       video.src = stream;                
       video.play();      
             }, errBack);           
    } else if (navigator.webkitGetUserMedia) {        
           navigator.webkitGetUserMedia(videoObj, function (stream) {          
             video.src = window.webkitURL.createObjectURL(stream);           
            video.play();           
        }, errBack);           
    }         
      //这个是拍照按钮的事件，          
     $("#snap").click(function () {          
         context.drawImage(video, 0, 0, 320, 320);     
              //CatchCode();           
    });           
          }, false);           
          //定时器         
  var interval = setInterval(CatchCode, "300");      
                         //这个是 刷新上 图像的        
   function CatchCode() {        
       $("#snap").click();
//实际运用可不写，测试代 ， 为单击拍照按钮就获取了当前图像，有其他用途    
           var canvans = document.getElementById("canvas"); 
//获取浏览器页面的画布对象                       
   //以下开始编 数据   
                                  var imgData = canvans.toDataURL(); 
//将图像转换为base64数据
               var base64Data = imgData.substr(22); 
//在前端截取22位之后的字符串作为图像数据       
                            //开始异步上             
   $.post("uploadImgCode.ashx", { "img": base64Data }, function (data, status) {      
             if (status == "success") {                 
      if (data == "OK") {                
           alert("二维 已经解析");                   
    }                    
   else {              
             // alert(data);          
             }          
         }     
              else {   
                    alert("数据上 失败");                 
  }               }, "text");           
          }      
 </script> 

后台代码：

public void ProcessRequest (HttpContext context) {    
      string img;//接收经过base64编 之后的字符串    
      context.Response.ContentType = "text/plain";        
  try       {           
   img =context.Request["img"].ToString();
//获取base64字符串          
    byte[] imgBytes = Convert.FromBase64String(img);
//将base64字符串转换为字节数组            
  System.IO.Stream stream = new System.IO.MemoryStream(imgBytes);
//将字节数组转换为字节流      
        //将流转回Image，用于将PNG 式照片转为jpg，压缩体积以便保存。         
     System.Drawing.Image imgae = System.Drawing.Image.FromStream(stream);    
          imgae.Save(context.Server.MapPath("~/Test/") + Guid.NewGuid().ToString()+".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);//保存图片             
 context.Response.Write("OK");//输出调用结果                
   }          catch (Exception msg)          {             
 img = null;            
  context.Response.Write(msg);      
        return;               
    }              
     }

代码来源：http://bbs.9ria.com/thread-215588-1-1.html